Actually, the error in this case is:
This is a variant of a server command overflow. It is caused by too many vars being set on players at the same time, and is exacerbated by the server trying to parse other client data sets at the same time.Code:Com_BeginParseSession: session overflow trying to parse [data name]
SOLUTION:
1. Lower the number of player slots;
2. Try not to set too many vars on players when they are connecting. Move some of it to other places like onJoinedTeam();