[VEN]

Your code contain

    register_event("ResetHUD", "roundMoney", "be")

but it not contain roundMoney function - that will cause an error.

This is not new round but round start (freezetime end)

    register_logevent("new_round", 2 , "1=Round_Start");

You should use that

register_event("HLTV", "event_new_round", "a", "1=0", "2=0")

EDIT:

And you do not need to return anithing in givemoney function

public givemoney(id)
{ 
    new cVar = get_cvar_num("round_money") 
    if(cs_get_user_money(id) < cVar) 
            cs_set_user_money(id, cVar) 
}