The machine is running FC5test1 updated to 2006-01-04.

Running standalone:

cagney@tomago$ /notnfs/cagney/native/frysk-gui/frysk/gui/FryskGui
could not create widget: java.lang.NullPointerException
Exception in thread "main" java.lang.NullPointerException
   at frysk.gui.monitor.MainWindow.<init> (MainWindow.java:57)
   at frysk.gui.monitor.WindowManager.initWindows (WindowManager.java:75)
   at frysk.gui.FryskGui.<init> (FryskGui.java:118)
   at frysk.gui.FryskGui.mainGui (FryskGui.java:148)
   at frysk.gui.FryskGui.main (FryskGui.java:233)

under gdb

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1208723792 (LWP 18942)]
0x0782114f in org.gnu.gtk.Widget.removePackageName(java.lang.Class) (
    klass=@79af9c0) at src/java/org/gnu/gtk/Widget.java:1249
1249            int length = klass.getPackage().getName().length();

java.lang.Class.getPackage is returning <<NULL>> which, as far as I know, can't
happen.

--

The package "org.gnu.gtk" is no longer being registered when loaded (?) and
consequently a search for it fails.

Under RHEL-4 and FC-4, the org.gnu.gtk package was being registering itself so
the above search worked.

Tom's come up with a testcase, that I'll attach.  It, however, also fails on
both FC-4/RHEL-4 and FC-5.  This suggests that there are two potential problems:
the issue identified by the testcase; and the apparent regression.