[Plugin: The Events Calendar] Upgrade from 1.0 to 1.2 not working

Help! I’ve been messing with upgrading my WordPress sites to the latest version of Premium Calendar (their Pro version) from 1.0 to 1.2 and it’s not working. I’ve tried everything I know to do – resetting permalinks, delete all plugin files and re-install several times, gone to the discussion board, even removed and re-installed other plug-in’s for potential conflicts, all to no avail.

Strange thing is I can create new events and can even access my old events I created when using 1.0 and had no problems with it. But when I go to view post, I get either “Opps, it looks like this page does not exist anymore. If you are lost try using the search box below.”And I’m still getting “or I get “Home /
Catchable fatal error: Object of class WP_Error could not be converted to string in /users/bravehearts.net/htdocs/wp-content/themes/reviewit-theme 4/reviewit/functions.php on line 99″.

This is a real drag because I loved using this premium plug-in (and yes, I paid for the upgrade to Pro). But if someone can’t help me debug this fast, I’m done with it and moving on to something else that works (ahhh, the beauty of Open Source).

So help please, or else adios.