I just upgraded from 1.1.4 and everything looked like it went smoothly with the exception I can't get to any of my boards or my topics.
I suspect the problem lies with SEO Friendly URLs. When I initially set up my SMF forum, I stupidly checked off to use the SEO urls. After a few months I decided I didn't want it that way and unchecked it. I had the exact same results as what I'm getting now.
Everything worked except I couldn't get to my boards/topics. Once I reapplied the seo urls, everything was fine again.
Did I do something wrong in the upgrade to cause this? The seo friendly urls box is still checked in my admin.
Help!

Almost forgot...here is a link if it will help:
http://thecrabbyhost.com [nofollow]