Are you referring to WHM bandwidth or bandwidth calcs in bandmin?
To try to get the WHM bandwidth calculating.. try:
/scripts/runweblogs
/scripts/fixsubdomainlogs
I just came in here looking to see if anyone else's bandmin is going crazy. My bandwidth in WHM is okay, banwidth totals in bandmin are okay to and match up closely with my MRTG... the only strange thing is that it is only showing the server IP stats and broadcast.. all the other IP accounts on the server aren't getting listed.. even though they all have more than 1mb of bandwidth already for the month. Strange... any ideas?