I'm seeing the same on x86_64.  When I launch Krita the window never comes up, but 'top' shows it as using 100% CPU time. Karbon does the same thing.

All my packages are up to date with F15 fedora-updates-testing as of this posting.

It's probably not a KDE problem because the same versions of Krita and Karbon work for me on F14.

I'll do some digging by preliminary strace/gdb investigating seems to imply it's hanging in some 'malloc' call.

okie dokie, here's a gdb backtrace from a hung krita on startup:

#0  0x00000030f21b2c3d in (anonymous namespace)::String::String (this=0x7fffa09202f0, c=-1 '\377')
    at /usr/src/debug/OpenGTL-0.9.15/OpenGTL/GTLCore/String.cpp:59
#1  0x00000030eba1b23d in (anonymous namespace)::TemplateLexer::nextToken (this=0x7fffa0920910)
    at /usr/src/debug/OpenGTL-0.9.15/OpenCTL/OpenCTL/templatecompiler/TemplateLexer.cpp:74
#2  0x00000030eba1b777 in (anonymous namespace)::TemplateParser::getNextToken (this=0x7fffa0920940)
    at /usr/src/debug/OpenGTL-0.9.15/OpenCTL/OpenCTL/templatecompiler/TemplateParser.cpp:275
#3  0x00000030eba1c364 in (anonymous namespace)::TemplateParser::parse (this=0x7fffa0920940)
    at /usr/src/debug/OpenGTL-0.9.15/OpenCTL/OpenCTL/templatecompiler/TemplateParser.cpp:258
#4  0x00000030eba148bb in (anonymous namespace)::Template::compile (this=0x2d8e0a0) at /usr/src/debug/OpenGTL-0.9.15/OpenCTL/OpenCTL/Template.cpp:118
#5  0x00007f5a445828d8 in CTLCSPlugin::CTLCSPlugin (this=<optimized out>, parent=<optimized out>) at /usr/include/QtCore/qbytearray.h:383
#6  0x00007f5a44583f47 in KPluginFactory::createInstance<CTLCSPlugin, QObject> (parentWidget=<optimized out>, parent=<optimized out>, args=...)
    at /usr/include/kde4/kpluginfactory.h:473
#7  0x00000030e88203e9 in KPluginFactory::create (this=0x1bd0f60, iface=0x30e5a13e00 "QObject", parentWidget=0x0, parent=0x1af5950, args=..., 
    keyword=<optimized out>) at /usr/src/debug/kdelibs-4.6.1/kdecore/util/kpluginfactory.cpp:203
#8  0x00007f5a54ed41ce in create<QObject> (parent=0x1af5950, args=..., keyword=..., parentWidget=0x0, this=0x1bd0f60) at /usr/include/kde4/kpluginfactory.h:527
#9  createInstance<QObject> (error=0x7fffa09212d0, args=..., parent=0x1af5950, parentWidget=0x0, this=0x1bcff80) at /usr/include/kde4/kservice.h:551
#10 createInstance<QObject> (error=0x7fffa09212d0, args=..., parent=0x1af5950, this=0x1bcff80) at /usr/include/kde4/kservice.h:528
#11 KoPluginLoader::load (this=0x1af5950, serviceType=<optimized out>, versionString=<optimized out>, config=...)
    at /usr/src/debug/koffice-2.3.3/libs/koplugin/KoPluginLoader.cpp:120
#12 0x00007f5a551124a5 in KoColorSpaceRegistry::init (this=0x1bc6100) at /usr/src/debug/koffice-2.3.3/libs/pigment/KoColorSpaceRegistry.cpp:100
#13 0x00007f5a55112d48 in KoColorSpaceRegistry::instance () at /usr/src/debug/koffice-2.3.3/libs/pigment/KoColorSpaceRegistry.cpp:69
#14 0x00007f5a550ff74d in KoColor::KoColor (this=0x7f5a44c1c8c0) at /usr/src/debug/koffice-2.3.3/libs/pigment/KoColor.cpp:51
#15 0x00007f5a449e0e32 in __static_initialization_and_destruction_0 (__priority=65535, __initialize_p=1)
    at /usr/src/debug/koffice-2.3.3/krita/plugins/paintops/libpaintop/kis_color_source.cpp:28
#16 _GLOBAL__sub_I_kis_color_source.cpp(void) () at /usr/src/debug/koffice-2.3.3/krita/plugins/paintops/libpaintop/kis_color_source.cpp:237
#17 0x00000030dac0ea36 in call_init (l=<optimized out>, argc=1, argv=0x7fffa0923278, env=0x195bef0) at dl-init.c:83
#18 0x00000030dac0eb13 in call_init (env=<optimized out>, argv=<optimized out>, argc=<optimized out>, l=<optimized out>) at dl-init.c:50
#19 _dl_init (main_map=0x1bc9090, argc=1, argv=0x7fffa0923278, env=0x195bef0) at dl-init.c:132
#20 0x00000030dac12dc2 in dl_open_worker (a=<optimized out>) at dl-open.c:464
#21 0x00000030dac0e8a6 in _dl_catch_error (objname=0x7fffa0921a98, errstring=0x7fffa0921aa0, mallocedp=0x7fffa0921aaf, operate=0x30dac12a30 <dl_open_worker>, 
    args=0x7fffa0921a50) at dl-error.c:178
#22 0x00000030dac1330a in _dl_open (file=0x1bc8e58 "/usr/lib64/kde4/kritadefaultpaintops.so", mode=-2147483647, caller_dlopen=0x30e594cbab, nsid=-2, argc=1, 
#23 0x00000030db400f26 in dlopen_doit (a=0x7fffa0921c70) at dlopen.c:67
#24 0x00000030dac0e8a6 in _dl_catch_error (objname=0x19cb2d0, errstring=0x19cb2d8, mallocedp=0x19cb2c8, operate=0x30db400ec0 <dlopen_doit>, args=0x7fffa0921c70)
    at dl-error.c:178
#25 0x00000030db40152f in _dlerror_run (operate=0x30db400ec0 <dlopen_doit>, args=0x7fffa0921c70) at dlerror.c:164
#26 0x00000030db400fc1 in __dlopen (file=<optimized out>, mode=<optimized out>) at dlopen.c:88
#27 0x00000030e594cbab in QLibraryPrivate::load_sys (this=0x1b511d0) at plugin/qlibrary_unix.cpp:205
#28 0x00000030e5947f95 in QLibraryPrivate::loadPlugin (this=0x1b511d0) at plugin/qlibrary.cpp:478
#29 0x00000030e8821a58 in KPluginLoader::load (this=0x7fffa0922100) at /usr/src/debug/kdelibs-4.6.1/kdecore/util/kpluginloader.cpp:224
#30 0x00000030e8821d29 in KPluginLoader::factory (this=<optimized out>) at /usr/src/debug/kdelibs-4.6.1/kdecore/util/kpluginloader.cpp:189
#31 0x00007f5a54ed4189 in createInstance<QObject> (error=0x7fffa0922360, args=..., parent=0x1af5950, parentWidget=0x0, this=0x1bc59c0)
    at /usr/include/kde4/kservice.h:549
#32 createInstance<QObject> (error=0x7fffa0922360, args=..., parent=0x1af5950, this=0x1bc59c0) at /usr/include/kde4/kservice.h:528
#33 KoPluginLoader::load (this=0x1af5950, serviceType=<optimized out>, versionString=<optimized out>, config=...)
    at /usr/src/debug/koffice-2.3.3/libs/koplugin/KoPluginLoader.cpp:120
#34 0x00007f5a55ffd7ac in KisPaintOpRegistry::instance () at /usr/src/debug/koffice-2.3.3/krita/image/brushengine/kis_paintop_registry.cc:62
#35 0x00007f5a5647d5de in KisFactory2::componentData () at /usr/src/debug/koffice-2.3.3/krita/ui/kis_factory2.cc:118
#36 0x00007f5a5647de9a in KisFactory2::KisFactory2 (this=0x1b0b370, parent=0x0) at /usr/src/debug/koffice-2.3.3/krita/ui/kis_factory2.cc:60
#37 0x00007f5a48d72b3f in qt_plugin_instance () at /usr/src/debug/koffice-2.3.3/krita/krita_part_init.cc:24
#38 0x00000030e8821db0 in KPluginLoader::factory (this=0x7fffa0922900) at /usr/src/debug/kdelibs-4.6.1/kdecore/util/kpluginloader.cpp:201
#39 0x00007f5a55c7959f in createInstance<KoDocument> (error=0x7fffa0922930, args=..., parent=0x0, parentWidget=0x0, this=0x1b024a0)
    at /usr/include/kde4/kservice.h:549
#40 createInstance<KoDocument> (error=0x7fffa0922930, args=..., parent=0x0, this=0x1b024a0) at /usr/include/kde4/kservice.h:528
#41 KoDocumentEntry::createDoc (this=<optimized out>, errorMsg=0x7fffa0922c50, parent=0x0) at /usr/src/debug/koffice-2.3.3/libs/main/KoDocumentEntry.cpp:58
#42 0x00007f5a55c63ded in KoApplication::start (this=<optimized out>) at /usr/src/debug/koffice-2.3.3/libs/main/KoApplication.cpp:140
#43 0x00007f5a5680f419 in kdemain (argc=<optimized out>, argv=0x7fffa0923278) at /usr/src/debug/koffice-2.3.3/krita/main.cc:46
#44 0x00000030db02131d in __libc_start_main (main=0x4008d0 <main(int, char**)>, argc=1, ubp_av=0x7fffa0923278, init=<optimized out>, fini=<optimized out>, 
    rtld_fini=<optimized out>, stack_end=0x7fffa0923268) at libc-start.c:226
#45 0x0000000000400901 in _start ()

confirmed it's an OpenGTL issue (90% sure anyway), I'll file a separate bug and block this one that one.

*** Bug 690833 has been marked as a duplicate of this bug. ***

OpenGTL-0.9.15-3.fc15 has been submitted as an update for Fedora 15.
https://admin.fedoraproject.org/updates/OpenGTL-0.9.15-3.fc15

Package OpenGTL-0.9.15-3.fc15:
* should fix your issue,
* was pushed to the Fedora 15 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing OpenGTL-0.9.15-3.fc15'
as soon as you are able to.
Please go to the following url:
https://admin.fedoraproject.org/updates/OpenGTL-0.9.15-3.fc15
then log in and leave karma (feedback).

I can confirm that krita now executes. I was able to open a picture file with it.
So it seems fixed.

-----

koffice-krita.x86_64           3:2.3.3-4.fc15      @updates-testing
koffice-krita-libs.x86_64      3:2.3.3-4.fc15      @updates-testing

OpenGTL.x86_64                 0.9.15-3.fc15       @updates-testing          
OpenGTL-debuginfo.x86_64       0.9.15-3.fc15       @updates-testing-debuginfo
OpenGTL-libs.x86_64            0.9.15-3.fc15       @updates-testing

OpenGTL-0.9.15-3.fc15 has been pushed to the Fedora 15 stable repository.  If problems still persist, please make note of it in this bug report.