Edit: when I saw the comment to CommonsWare answer I did not realize it was the same as the asker... anyways, a little explanation may be useful for somebody.
As yourself commented, the easiest way to uninstall a system app is plainly to delete the
.apk file. The
adb install /
adb uninstall commands are useful for regular apps, not system apps. Since this apk is located in
adb uninstall will not remove it.
You can use the command suggested (
rm /system/app/YourApp.apk), but before the
/system folder need to have write access. You will need to see how to
/system in your specific device, try searchig for "
android remount +rw /system" and your device).
Alternatively, you may use any app that can do both deletion and remounting and has root access, such as Root Explorer and Astro