I know that problem, because of your lag you sent too many signals to vent at once and it autobanned you, go to the ventrilo contest ban forums and create a thread using this format to get unbanned and tell them about the ban.
Unbanned, please slow down a little next time so you don't get autobanned for switching channels too fast. If this happens again, please post in the "Ventrilo Contest Ban" section of the forums.