#define CONVERTING 1000

CMD:convert( playerid, params[ ] )
{
 	ShowPlayerDialog(playerid, CONVERTING, DIALOG_STYLE_LIST, "Converting Money,Coins,Score.",""COLOR_LIGHTBLUE"1000000$ {FFFFFF}-> {5D66CC}100 Coins\n"COLOR_LIGHTBLUE"1000000$ {FFFFFF}-> {5D66CC}1 Score\n"COLOR_LIGHTBLUE"100 Coins {FFFFFF}-> {5D66CC}1000000$\n"COLOR_LIGHTBLUE"100 Coins {FFFFFF}-> {5D66CC}1 Score\n"COLOR_LIGHTBLUE"1 Score {FFFFFF}-> {5D66CC}1000000$\n"COLOR_LIGHTBLUE"1 Score {FFFFFF}-> {5D66CC}100 Coins","Convert","Cancel");
	return 1;
}

public OnDialogResponse(playerid, dialogid, response, listitem, inputtext[])
{
  	if(dialogid == CONVERTING)
	{
		if(response)
		{
			if(listitem == 0)
			{
				if ( GetPVarInt( playerid, "Money" ) < 1000000 )
				    return SendClientMessage( playerid, -1, "You need 1000000$ to get 100 Coins!");
				    
				SetPVarInt(playerid, "Coins", GetPVarInt(playerid,"Coins") + 100);
				GivePlayerMoney(playerid, -1000000);
				SCM(playerid,COLOR_DGREY,"You got 100 Coins for 1000000$.");
			}
			if(listitem == 1)
			{
				if ( GetPVarInt( playerid, "Money" ) < 1000000 )
				    return SendClientMessage( playerid, -1, "You need 1000000$ to get 1 Score!");
				    
				SetPlayerScore(playerid,GetPlayerScore(playerid) +1);
				GivePlayerMoney(playerid, -1000000);
				SCM(playerid,COLOR_DGREY,"You got 1 Score for 1000000$.");
			}
			if(listitem == 2)
			{
				if ( GetPVarInt( playerid, "Coins" ) < 100 )
				    return SendClientMessage( playerid, -1, "You need 100 Coins to get 1000000$!");
				    
				GivePlayerMoney(playerid, 1000000);
				SetPVarInt(playerid, "Coins", GetPVarInt(playerid,"Coins") - 100);
				SCM(playerid,COLOR_DGREY,"You got 1000000$ for 100 Coins.");
			}
			if(listitem == 3)
			{
				if ( GetPVarInt( playerid, "Coins" ) < 100 )
				    return SendClientMessage( playerid, -1, "You need 100 Coins to get 1 Score!");

				SetPlayerScore(playerid,GetPlayerScore(playerid) +1);
				SetPVarInt(playerid, "Coins", GetPVarInt(playerid,"Coins") - 100);
				SCM(playerid,COLOR_DGREY,"You got 1 Score for 100 Coins.");
			}
			if(listitem == 4)
			{
				if ( GetPVarInt( playerid, "Score" ) < 2 )
				    return SendClientMessage( playerid, -1, "You need minimum 2 Score to get 1000000$!");

				GivePlayerMoney(playerid, 1000000);
				SetPlayerScore(playerid,GetPlayerScore(playerid) -1);
				SCM(playerid,COLOR_DGREY,"You got 1000000$ for 1 Score.");
			}
			if(listitem == 5)
			{
				if ( GetPVarInt( playerid, "Score" ) < 2 )
				    return SendClientMessage( playerid, -1, "You need minimum 2 Score to get 100 Coins!");

				SetPVarInt(playerid, "Coins", GetPVarInt(playerid,"Coins") + 100);
				SetPlayerScore(playerid,GetPlayerScore(playerid) -1);
				SCM(playerid,COLOR_DGREY,"You got 100 Coins for 1 Score.");
			}
		}
		else
		{
		SCM(playerid,COLOR_DGREY,"You closed.");
		}
	}
	return 1;
}

if ( GetPVarInt( playerid, "Score" ) < 2 )//this is your current code, test using 
if(GetPlayerScore(playerid) < 2)//test using this and see if you get the same problem, then it's somthing that is badly wrong, othervise you have just forgot to assign the PVar the value of the players score