[Zope] ZSQLRelayDA

I'm trying to use ZSQLRelayDA to access a MS SQL database on a windows server from a Zope instance on a linux server. I can issue one query, then I get an error printed to the console of the linux box when I try to issue another: "Client Library error: severity(78) layer(0) origin(0) number(51) Error: Attempt to initiate a new SQL Server operation with results pending." Zope hangs, and needs to be restarted. It looks like either zope or sqlrelay isn't closing the database connection properly. Anyone any ideas of how to fix this? Robert Munro