Description of problem:
I have once killed (kill -9) PackageKit during an update. Since then, when I start Apper it only shows UPDATES, INSTALLED SOFTWARE and SOFTWARE SOURCES options. If I enter Software Sources and click on some repo, I get a window with the following message: failed to search: <repo> is not enabled after md load. If I choose Updates and then click on Verify Updates, I get a window with the following message: failed to get updates: nothing to do as no stores in stores array. All my repo are enabled and I can do all operations through yum or yumex. Also, I have already removed and reinstalled PackageKit and Apper. None of this solved the issue. Googling the error messages dont bring me any usefull results.

I have alread filled a bug against Apper (https://bugs.kde.org/show_bug.cgi?id=314129), but they bounce me back to Fedora as a PackageKit/yum bug.

Every time some program tries to auto-install a package or Apper tries to check updates, I got a PackageKit crash (via abrt).

Reproducible: Always

Steps to Reproduce:
1. Open Apper;
2. Choose Updates;
3. Click on verifiy new uptades;

 or

1. Open Apper;
2. Choose Software Sources;
3. Click on any repo; Actual Results: If I enter Software Sources and click on some repo, I get a window with the following message: failed to search: <repo> is not enabled after md load. If I choose Updates and the click on Verify Updates, I get a window with the following message: failed to get updates: nothing to do as no stores in stores array. Expected Results: It should show a categorized list of softwares (kde, office, etc.) in addition to the options exibhited. 

If the steps aboves are followed, they should give a list of available packages or open repo informations. 

Distro version: Fedora release 18 (Spherical Cow)
NAME=Fedora 
VERSION="18 (Spherical Cow)" 
ID=fedora VERSION_ID=18 PRETTY_NAME="Fedora 18 (Spherical Cow)" 
ANSI_COLOR="0;34" 
CPE_NAME="cpe:/o:fedoraproject:fedora:18" Fedora release 18 (Spherical Cow) 
PackageKit version: 0.8.7 PackageKit Process Information: root 2531 0.3 5.0 818284 198188 ? Sl 09:32 0:01 /usr/libexec/packagekitd

Version-Release number of selected component:
PackageKit-0.8.7-1.fc18

Additional info:
backtrace_rating: 4
cmdline:        /usr/libexec/packagekitd
crash_function: g_vasprintf
executable:     /usr/libexec/packagekitd
kernel:         3.7.5-201.fc18.x86_64
uid:            0

Truncated backtrace:
Thread no. 1 (10 frames)
 #9 g_vasprintf at /lib64/libglib-2.0.so.0
 #10 g_strdup_vprintf at /lib64/libglib-2.0.so.0
 #13 zif_download_location_full at /lib64/libzif.so.5
 #14 zif_store_remote_load_metadata at /lib64/libzif.so.5
 #15 zif_store_remote_resolve at /lib64/libzif.so.5
 #16 zif_store_resolve_full_try at /lib64/libzif.so.5
 #17 zif_store_resolve_full at /lib64/libzif.so.5
 #18 zif_store_array_repos_search at /lib64/libzif.so.5
 #19 pk_backend_get_updates_thread at /usr/lib64/packagekit-backend/libpk_backend_zif.so
 #20 pk_backend_job_thread_setup