A while ago, a customer experienced some issues whenever he tried to edit a document or create a new document from withing SharePoint Server 2007. Apparently this was caused by using Office 2003, installing and removing beta versions of Office 2007 and afterwards performing a new install of Office 2007 RTM. This article - Internet Explorer crashing when launching documents Office documents from SharePoint Server and WSS suggested performing a reinstall of the "Windows SharePoint Services support" in Office 2007 but fortunately one of our SharePoint gurus found a quicker workaround:
1. Delete C:\Program Files\Microsoft Office\Office 12\OWSSUPP.DLL
2. Run the Microsoft Office Diagnostics tool (Start > All Programs > MS Office > MS Office Tools)
This seemed to solve the issue.