Jdbc problem on websphere

I am trying to run jsp & servlets which connect to a lotus database. I’ve installed the lotus jdbc driver as in the docs and installed the PATH enviroment variable. My applications were working right till this morning, but now they are not. I’am getting:java.lang.NoClassDefFoundError: lotus/jdbc/domino/DominoDriver error and can’t access to lotus. Is it about the classloader?

Subject: Jdbc problem on websphere

well, after a fresh restart it works again. But i am sure not for too long. I still don’t know the real problem.