[!Phoenix!]

pawn Код:

stock WorldLibero(worldid)
{
    if(worldid==0)return false;
    for(new i = 0; i < MAX_PLAYERS; i++) // Here you start a loop, but where does it start and where does it end?
    //  {
    if(GetPlayerVirtualWorld(i) == worldid) /* break removed */ return false;
    //  }
    return true;
}

The same with the while-loop in your second code snippet.

https://sampwiki.blast.hk/wiki/Loops

If it's at all possible to run a loop without start/end tag you should write it all in one row, I think.