It's a known bug, fixed by 5.0a which MS will send you for free if you report you are experiencing the bug to them. It's documented in MS Knowledgebase article
Q156866. Workarounds includde leaving off the prompt clause, but really the best solution is to get 5.0a. Check the article at the MS web site (www.microsoft.com/kb) for other workarounds, like reinstalling the drivers, til you get the new version.

Typically they ask that you lit a bug you are experiencing that is fixed by the patched version before they ship it to you for free...