That's a pretty standard error if a resource in the pool is invalid when its closed, e.g. if validation is on and someone had restarted the database with the application server up then you'd see these for sure.
Turning the logging to FINE should show the exception the pool caught when it was closing the connection.
That's also the 7.1 FCS release, so there are JDBC defects, that are fixed in the later update releases, that could have an impact.
If its 7.1 EE then we never, as far as I am aware, put publicly available downloads up on our external websites - contracted customers should have been able to download any patches/releases via their online support account.
If this is a 7.1 SE then this is the link to the 7.1 UR6 SE bundle:
http://www.sun.com/download/products.xml?id=468dc166 though this of course shouldn't be used to upgrade an EE version.
7.1 officially entered Sun's EOL process in October 2007 and any sort of maintenance support ends October 2008.
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