This is an internal extended system stored procedure that gets called to prepare and execute an ODBC batch in one round trip to the server.  There is a detailed thread about this in Google Groups - search for "ODBC and SQL 2000" (including the leading and trailing double-quotes) in Google Groups, and look for the posts from October 2003, most of which are from Billy Yao and Lance Johnson.

Hope this helps!

Chris

PS.  I would like to take this moment to commemorate my 150th post!  When do I get paid?    

Just kidding, all you 5000-post animals...