I'm also having this problem and this is what I've found so far:
http://www.orindasoft.com/public/PL-SQL%20Recordstwo.php4?siteloc=PL-SQL%20Recordstwo#probva
This is known to occur under when you are using too big an array size. How big your array can be depends on the length of each record and the Driver/Database combination. If you exceed the maximum size you will get the "OALL8" SQLException and your connection object may become unusable.
This message is also created if you are using the following:
9.0.1 Database
10.1.0 JDBC Driver
Generated Code that passes in an ARRAY or VARRAY of VARCHAR2 as a Parameter