Hi Maurizio,
Start to check if there is a a a file $pwrp_db/xxx.wb_load where xxx is the name of the class volume. This should be created when creating a new ClassVolumeConfig object but this is not always done in V4.5.0. If the file doesn't exist you can create it by hand, it is text file, and write the volume name and the volume identity in it for example
[code:1]Volume MyClassVolume $ClassVolume 0.0.55.55
EndVolume[/code:1]
where MyClassVolume is the volume name and 0.0.55.55 the volume identity.
/Claes