Hallo,
vielleicht hift Dir dies:

Check for authority and authorization lists with the Work Link ( WRKLNK ) command on the root directory (WRKLNK '/'), and select Option 9 to Work with Authority. Check for any authorization lists and also what the setting is for *PUBLIC. Share files must have read/write capability. If this is set correctly, do an F12 to get back to the root directory, and select Option 5 to Display. The user must drill down the tree and check the authority along the way.

There is an informational APAR II09493 that discusses CLIENT ACCESS NETWORK DRIVE TROUBLESHOOTING. Share files must also have read/write capability. In Operations Navigator, right-click on the share file, select Properties , and change the access to a minimum of read/write.