ORA-01000 in webapp despite number of open cursors nowhere near open_cursors

Hi,

A webapp uses a connection pool (c3p0) to connect to an 11.2.0.3 EE database.

I monitor the number of open cursors per session with a pair of queries that run in a cron job every minute:

select max(a.value) as highest_open_cur
from v$sesstat a, v$statname b
where a.statistic# = b.statistic#
and b.name = 'opened cursors current';

and

select max(count(oc.sql_id))
from v$OPEN_CURSOR oc, v$session se
where oc.sid = se.sid
group by oc.sid, oc.USER_NAME
order by count(*) desc;

The webapp gets fairly regular ORA-01000 errors.