There are worms that spread though instant messaging like MSN but not BlackBerry Messenger. F-Secure Computer Virus Information Pages: IM-Worm
They won't infect the BlackBerry however. And I have gotten plenty of spam with dates in the future like 2069.
makulaf, is it possible she could have gotten it by email instead of BBM and maybe was confused? Or does she have another IM app on her BlackBerry?
The sender can be spoofed, making it look like if came from you, for example, when it really didn't.