users cant access forum help

[Erwin]

They can't just log on normally as their cookie domains have changed. The best thing to do is to:

1) Take your forum offline for 48 hours, until the DNS propagates, and then your users can go online again.

OR

2) Change the $bburl setting by changing the URL of your site in vB Options, and the cookie domain in vB Options, to reflect the IP address (if available) of your new server until the DNS info propagates.

I would go with option 1. Moving servers is always a headache.