Here's one that you might come up against if you are using the Microsoft Office SharePoint Server 2007 Technical Refresh. I was trying to create a new workflow for a document library through the browser. However, when I tried to access the second page in the wizard, I got the following error:
There has been a critical error while processing the form.
Click Start Over to load a new copy of the form. If this error persists, contact the support team for the Web site.
Click Close to exit this message.
Details: Too many bytes in what should have been a 7 bit encoded Int32.
The fix for me was quite straightforward
1. Run stsadm -o reconvertallformtemplates
2. Delete your internet explorer browsing history