By the following answers you gave me to these two questions:
1. What ISP are you on?
-I'm using AOL
3. Did you receive notifications before the move?
-yes i always recieved them b4 the move
Tells me this - This IS due to the server change and the fact AOL and other ISP are blocking mail from RCNT because our data center is listed on a SPAM list. The forum software just doesn't stop sending email notifications just for the fun of it, again it's because of the SPAM list. If you have tried doing what Waste Land was kind enough to point out as a fix and you're still not getting them then it's something to do with AOL blocking it out completely.
However good news for you and others, I have requested our server be given a new IP, the request was approved and the new IP should take effect anytime now. This should fix most if not all of the problems regarding email notifications.
-Michael