Hi,
In the absence of any other errors output discards are indicative of transient oversubscription. Whether it's an actual problem or not depends on how sensitive the applications on the port are to packet loss.
The number by itself is meaningless - you need to divide it by the total packets output to get a percentage packet loss. If it's a very small number (e.g. <0.001%) then it's unlikely to be an issue, but as the % increases so does the risk that it might be service affecting.
There's no absolute answer to how much packet loss is acceptable - a callmanager server will be critically affected by a very small amount of packet loss but an ftp server can handle a much larger amount.
HTH
Andrew.