[m4karow]

the sendclientmessage function returning with 1... you need to return with 0.

public OnPlayerRequestSpawn(playerid)
{
if(gTeam[playerid] == FBI && GetPlayerCop(playerid, pInfo[playerid][Cop]) < 100) return SendClientMessage(playerid, COLOR_RED,"You need 100 cop skills to spawn as F.B.I "), 0;
return 1;
}