There's one other thing that might cause a problem. Microsoft Access, if that's what you're using, doesn't support COUNT DISTINCT. (At least, it didn't in Access 97. I don't have Access 2000 or 2003, so I can't test it.)
To get around this, just use a saved query, which is the equivalent of a view in Access:
select distinct PlayPlayer
Save the above query as DistinctPlayersQuery. Note that you aren't saving any data, just the SQL. Then your count query becomes:
select count(*) as PlayerCount
Since the players are already distinct in the saved query, you can just count them.