PGA Memory Leak detected?

Whats a PGA Memory leak?

I issued a shutdown immediate for an 8.1.7 db running on Win2K.

It shutdown cleanly (or appeared to) and the sys admins resarted it by rebooting the server (the services and Db autostart).

Looking at the alert file, as the Db shutdown there was an ORA-00600: internal error code. This generated a trace file: sidRECO with the error PGA memory leak detected 7164 > 3544

Anyone have any idea whats going on here, because I don't?

Its usually best to raise an iTar for ORA-0600 problems - we've had a number of small issues with memory leaks - usually fixed by putting an event in the init.ora under instruction from support.
You can lookup your ORA-0600 error using
http://metalink.oracle.com/metalink/...&p_id=153788.1
and theres a note on small PGA memory leaks here:
http://metalink.oracle.com/metalink/...T&p_id=39308.1