Not sure what happened here... I ended up having to completely uninstall and remove CGBlog and all it's dependencies, and a couple of others, then reinstall them all from scratch. Bit of a ball ache but sorted now at least
Here's the modules I removed completely:
CGBlog
CGExtensions
CGFeedback
CGSimpleSmarty
jQueryTools
I then started by installing CGBLOG and let it install it's dependencies automatically... Then I put the other modules back on. I got busy with PhpMyAdmin to retain my data - backed up the DB tables for each module (anything prefixed 'CMS_MODULE_' followed by the module name, eg. CMS_MODULE_CGBLOG, CMS_MODULE_CGBLOG_CATEGORIES etc.), and backed up entries in the CMS_MODULES_TEMPLATES table relating to each of the above modules, then loaded them all back in one by one. Seems to be working ok now...
If anyone can find a more elegant solution it would probably save Panthus a lot of trouble!
*Edit* Just noticed that Panthus is using a clean install... now I'm really confused! If Panthus is getting these problems on a clean install it must be something above and beyond an upgrade anomally?