[UFF]

Код:

CMD:budget(playerid, params[])
{
	new string[500], str[500];
	format(string, sizeof(string), "Budget amount: %d\n", Budget);
	strcat(str, string);
	strcat(str, "\n");
	strcat(str, "text");
	ShowPlayerDialog(playerid, DIALOG_BUDGET, DIALOG_STYLE_MSGBOX, "Budget info", str, "OK", "");
	return 1;
}

You have to use str instead of string in ShowPlayerDialog.