Slightly old thread, not necessarily dead though...
Anyway, I came across it by searching for a fix for the plazmic simulator bug... still no fix it looks like
Anyway, DoctorN, just go into options, security, general, bb button -> wipe.... it will wipe the device of all the personal data (old themes you loaded on).
This is such a pain... I wish it just worked right in plazmic... what a buggy piece of software!