What version of vbulletin are you running now? The rewrite rules changed so make sure you are using the current ones contained in the do_not_upload/rewrite/forum directory. And, I suggest you uncomment the RewriteBase line and enter your forum directory there:

Hi guys, and thanks again for your support, it is appreciated ;)

snakes1100: I haven't done any permanent modifications to the /public_html/forum/.htaccess file. I have taken a look in there, and can't quite make out what it is you're asking. Do you mean I should delete any line that starts with RewriteRule so long as it's not sandwiched between # BEGIN WordPress and # END WordPress? Please let me know so that I can try ;)

Lynne: the version I'm currently running is vBulletin (4.1.12 Patch Level 2). All I know about it is the last guy that worked on these issues a few weeks ago told me he'd brought the forum and its files up to date. That's all I know and understand about that to be honest.

I followed your suggestion and uncommented the RewriteBase line and changed it to my forum directory. I couldn't believe my eyes when this modification then allowed me to access all the forums on the site – thank you :) To let you know what level I'm on with these issues, I had to first Google how to uncomment code in an .htaccess file before I could to understand your instructions.

So this seems to have resolved the forum access issue which is HUGE, but there's still the problem with accessing the adminCP. Snakes1100, you discovered this is probably being caused by something in the /public_html/forum/.htaccess file rules, so I look forward to trying you above suggestion when you have a moment to break down what I need to do.

Thanks one and all. We've made some great progress thanks to your input, and even if it doesn't get any better than this, at least the forum is live and accessible, directly, and the adminCP indirectly, with some disruption to the site while accessing this area.

Andy