PM box error

Wondering if someone can help me out with an issue I'm having.  I'm new to the web wiz forum software and web admin in general though I am an IT person.

I took over a site from someone and we just moved the forum and the databases to another server and everything appeared to be good to go.  All the threads, users etc were moved and seem to be working fine.  However when I go to my PM inbox I get the following error.

Microsoft VBScript runtime error '800a005e'

Invalid use of Null: 'CBool'

/forum/pm_inbox.asp, line 286

I see the outbox fine and can send PM's to a test account but when I login to the test account to retrieve the message I get this error there as well.  Any help would be greatly appreciated.  I am using version 9.56a.

Thanks

I got in touch with the guy that originally created the site and it sounds like there were some custom configurations he had on the PM database tables and when we transferred the site they were lost.  Once he re-implemented them the problem went away.