Problem during Upgrade 10.2.0.4

Hi Gurus !!!

During upgrade from 9.2 to 10.2 we have install 10.2.0.4 patches and now we are ready to call dbua (upgrade assistant).

When we call dbua an error occurs :

./dbua

Error message

Failed to load Main Class: oracle.sysman.assistants.dbma.Dbma

We've check enviroments variables and all are Ok.

Any ideas ?

Thanks in advance.