Sorry for the downtime people. Although it probably looked like I wasn't doing anything I was up till about 3am this morning trying to fix it, with no success.
Short version, the forum software wasn't compatible with an upgrade the hosts did. Thats been sorted for now at least.
Tech version, Hosts upgraded to php 5.3.1 which doesn't support ampersan, but this forum uses. I tried removing them but it didn't work. Tried switching off error reporting in htaccess and index files, didn't work. I didn't have access to php.ini to do the same as its shared hosting. The host downgraded php this morning and all is well.
Problem is, chances are sometime in the future they will probably have to upgrade again. Barring switching off error reporting, I don't see there is a fix, and I don't think the hosts will do this as its not a fix, and others would complain. So I'll have to look into 3 options
1. changing hosts, but same could happen again
2. changing forum software, don't really want to
3. Upgrading vbulletin, but its $205 and I'm dead opposed to paying for something thats not needed, just to basically fix sloppy programming. Considering the error I think vbulletin should allow the update for free.
So not sure which way to go lol
The 4th option is to use a nulled version of vbulletin, inserting my legit license number into the files, but for obvious reasons I don't want to go down that route