Hello Cdewar,
I'm going to email you a patch that writes the mailboxes.txt file in ANSI instead of Unicode.
You mentioned that your Exchange installation was actually an upgrade - this might well be the cause of the anomoly! We've sold hundreds of copies of the Exchange add-on, but only had about 3 reports of this error - so it may well be that this problem only occurs when a user has upgraded the installation.
I will email you that patch in the next few minutes.
Thank you,
Linus