Breaks finder. Cannot start finder

I have Mac OS X 10.7, Ubuntu 12.04, and Windows 7 sharing a common folder on an Ext3 partition, with Mac using ExtFS. I just upgraded from OS X 10.6 (Snow Leopard) to 10.7 (Lion), and get the odd behavior that everything on my Ext3 partition seems to be working except for MS Office (14.2.3). For example, when I open a .docx file on that partition, MSWord opens it Read-Only, but LibreOffice works just fine. It's only been a day or so now, and I haven't done a comprehensive analysis to see what other landmines might be lurking. I don't think I want to upgrade ExtFS until I've actually installed Mountain Lion. I'm trying to use Windows as rarely as possible, but I could probably re-boot to Windows if I really need to use MSOffice. Sigh.

Finder doesn't crash but upon installing it seemed to read the partitions on my phone until I rebooted. Disk Utility does have the option (not certain if it was there before) to create ext (ambiguously labeled "Extended File System") but it errors out before it is created [Unable to create "test.dmg." (No child processes)]. It could be Ext1 that it is trying to create but I don't know much about it. 10.7.5