Also, I've been noticing this message for awhile and finally decided to track it down:

"No player named 'xxx' is currently playing."

Lo and behold, the first google search result was this thread: http://www.dual-boxing.com/showthread.php?p=133965

I can't follow the instructions that you gave in the second post, Jafula, because I'm playing with only the one member in my team. (Another reason I'd like Jamba to 'disable' itself when only one team member exists. =D )