Are you talking about v$Open_cursor? I don't have a v$Open_query in my 8.1.6 database.

If so, v$open_cursor does not show recursive cursors that are open. These are internal queries that Oracle has to run to complete your queries. There may be enough internal queries that are using up your limit on open cursors.

I don't know of a way around this other than to change the init.ora parameter, but there may be a way that I am unaware of. ( I do know that you can't change this parameter on the fly with an 'alter system' command)

-John