"Unfortunately, Settings has stopped" even after factory reset

I am trying to fix a friend's Yarvik GoTab Zetta 9.2" Tablet (TAB466120507803).

Android version 4.0.3, Baseband version 1.1, Kernel version 3.0.8+ (inet_pmelive@InetSoftware), Build number 03F2-P1-H2-H01-1962.20120421,

I already tried a complete factory data reset (including erasing SD card) but the following problem persists:

Anytime I try to open "Language & Input" in the Settings, the whole Settings window is closed and I get the pop-up message: "Unfortunately, Settings has stopped".

With aLogcat I see that around the time of the error message, the log says:

W/dalvikvm ( 1301): threadid=1 thread exiting with uncaught exception (group=0x409f51f8)

As Yarvik seems to be bankrupt, I do not expect any feedback from them.

Any suggestions, how I could proceed?

Thanks!