BIS and OWA 2007

I am an IT Administrator running Exchange Server 2007 sp1 on a Server 2008 box.

Somehow the IIS details for OWA got deleted. I have now managed to get it all working again and OWA works a treat, but our company BlackBerrys don?t seem to want to communicate with OWA. The BlackBerry internet service returns the following error message:-

?An error occurred during email account validation. please check your information and try again.?

I have tweaked and changed and rechanged about every setting in the book.