ORA-08177 at SELECT in sqlobj$plan

This would be first posting in the Oracle communities, so please pardon if this is not the right category or the right place.

We have an Java based application that works with the database using OJDBC. We are ORA-08177 error while trying to run (what I believe is a) SELECT query on the sqlobj$plan table. I am not familiar with this table, but appears to be maintain the statistics to evaluate the query plan?

I realize ORA-08177 is seen when the isolation level is set to SERIALIZABLE and one session is trying to modify a data that the other session has modified since the transaction started. However, I do not see any modifications being done any of the user tables (all SELECT queries being fired).