EJB dependency library not found during server start-up

I've deployed an EJB module to Glassfish 2.1 and declared a library, which is located in the lib/applibs dir, as its dependencies. I deploy it using asadmin and the --libraries option to declare the dependency library.

That works during deployment of the EJB module. The classes from that library can be found without any problem.

But when I start Glassfish up, I get a NoClassDefFoundError about a class in this library.

Why do I get this error during startup and how can I fix it?

Thanks in advance.
Henrique