Have you made a system check before upgrading and an accredited graphic card with the latest driver?
That's a SINE QUA NIN!
Without a porper graphic card Allplan 2011 may not be operated and I strongly advise against making the upgrade to version 2011. It's their own fault, if anybody operates Allplan with a gamer-graphic card ... numerous system crash, surface elements aren't opening of files and so on...just to name a few problems you'll have with a non accredited graphic card.
Of course with a graphic card, accredited from Nemetschek yoou can't be 100% sure that everthing works perfect but at least you're on safe side.