Please, help: SQL Server and WebSphere security problem

I'm trying to roll updated data from Oracle DB to SQL Server 2000. My app runs on WebSphere 5.1 server. The app runs fine on my local machine. When it placed on dev server, it was able to connect to Oracle, but failed to connect to SQL Server. After java security was disabled, it runs without any problems. What need to be set or change so my app will run with security on?

Thank you.

We found out why it happened: some changes was made on the server and these changes cleared up after we restart the machine.