Can't Reply

I've searched the forums prior to posting and have been unable to find the specific problem I'm facing. It's very unusual, and I can't seem to figure out the source.

I'm using the BIS w/ a Gmail account. It was working fine, but now I can't reply to messages that have come to my BB from my Gmail account. I can reply to messages directly from the Blackberry support team, and I can compose messages and send them without a problem.

I'm at a loss at how to fix this. Any suggestions would be welcome.

Thanks