My friend keeps saying she gets the error message "Handle Invalid" after being logged into her key on Dream Seeker for approximately 5 minutes. Anyone know what the cause of this could be, and any ways to fix it? Thanks ahead of time.

This would more be a question for the makers of byond.
Anways, re-installing would be something I suggest. . .

Good luck, hope she figures it out.
There are two suggestions I have here. First, have your "friend" make a new key. You might need a new email for this but its just temporary. Second, if that failed to work, try haveing your "friend" use his/her key on your computer. If he/she still gets the problem, then I cannot help you and you should ask the Byond Makers (Dantom) otherwise, it is prolly the installation of his/her version of Byond on his/her computer. Always as helpful as I can be =P