I am working with autocad 2012LT on an iMac (lion)/parallels 6/win 7.every time I switch from model to paper space I get a fatal error.unhandeld e0434325h  7565d36h  or unhandeld e0434352   75b7d36hf.autocad is up to date.can anybody help me?

Have you done a search at the AutoDesk website on your error message?Unfortunately those who have made the choice to run AutoCAD for Mac have some problems that are unique only to that platform.  Those of us who run AutoCAD on a PC might not be familiar with Mac-related problems.