POST UPGRADE FAILED from 9.0.2 to 9.0.3

Hi All, 

I've recently upgraded my onsite installation SugarPRO from 9.0.2 to 9.0.3. I've tested the upgrade in a dev env and everything works fine. 

In production environment the post upgrade failed with a Notice php error and stopped the upgrade process. So I tried to rebuil config.php and did a quick rebuild and repair. 
The platform seems stable but non admin users could not log into anymore. Apache error log tells "Failed opening required 'modules/pmse_Inbox/engine/PMSEEngineUtils.php'" called by include/utils/autoloader.php on line 355,

It seems that this reuired is related to class-map and even clearing cache by deleting the class-map.php file doesn't solve the problem.

Any suggestion? Pmse module is related to workflof that are deprecated so i tried to delete the only one workflow present in the system but it doesn't work yet. 

Any suggestion?

Thanks in advance.

Regards,