Mission Loading Error

Hello All, I've searched and searched for an answer in the forums before posting for help. My engine runs great, I choose a mission to load and start the game just fine. When I exit the mission, I return to the missions list to choose another mission. Its then that I run into an error and I think its because I'm not ending the first one all the way. Heres the error I recieve:

Mapping string: MissionStartPhase2Ack to index: 1
Client 2828 packet error: Invalid packet GameBase::unpackUpdate().
CDROP: 2828 local

Now if I exit the engine all the way and restart it I can open a new mission no prob. Its only when I just exit to the missions list is where I get stuck on the second load. Thanx for any help in advance....