MSSQL Object has been closed error

I am using webMethods 6.0.1 on WIN200 with MSSQL database.
I am making calls to database to select a row in my mapping.
To make this calls I am using WmDB package.
I see this error

pub.db:execSQL java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Object has been closed.

Can anyone, help to fix this problem

no reason please help