[Mike_Peterson]

use this

pawn Code:

SetTimer("ScoreTimer",900000,true); // 900000 = 15 minutes

and this timer

pawn Code:

public ScoreTimer()
{
    for(new i = 0; i < MAX_PLAYERS; i++)
    {
    if(IsPlayerConnected(i))
    {
    SetPlayerScore(i,GetPlayerScore(i) + 1);
    }
}
}

this might do the trick