Administration with iManager 2.7.5 for Novell NetStorage

Hi.. I never used a forum before..
I have a problem to login into iManager. I got this error message:

Unable to create AdminNamespace. java.lang.NoClassDefFoundError: novell.jclient.JCException

I've installed Novell NetStorage 2.13.5 on a SLES 11 SP2 x64 server with the OES11 SP1 addon disk.
I configured the edirectory to a external Server over LDAP configuration.
Novell NetStorage works when I access it with a eDirectory user (server/netstorage). got also all the volumes and data I need as a normal user.
but when i want to acces the iManager as a administrator over server/nps i get the error.

I hope you can help me soon...