I have just done an upgrade to an old site of mine from 5.4.2.1 to 5.5.2.1 via 5.4.2.2 ready for a jump to 5.6.1 and did a whole load of block upgrades too. I have a copy of the site on a test server that I am working on till all the work is done and I can put the new version live.

I have Simple Blog installed but since the upgrade I am unable to access the blog pages, I am getting the following error:
An unexpected error occurred.
A database error occurred while processing this request.

I think somewhere along the line I have broken Simple blog.

As I was going to be restyling the blog any way I thought I would uninstall Simple Blog and reinstall it fresh and start again but when I try to uninstall I get a message and a 500 server error page:

http://mysite.com/index.php/dashboard/extend/install/do_uninstall_p... It may be down for maintenance or configured incorrectly.

I am guessing this is something to do with either the block upgrade or the core upgrade but not sure which.

Can any one suggest anything?