Found the issue:
On my B4J Folder I've 50 or so files (copies, backups, versions,etc) ; also I've a Folder for shareable Modules where I've downloaded the correct DBRequestManager.bas.
When adding the existing module from shareable folder in the IDE -> Project -> Add Existing Modules, the module continues to be the 'old' one; searching in the app folder I've found the 'old' DBRequestManager.bas; renaming and repeating the operation solved the problem (the new one is loaded)
Can be this to be considered as a bug ? (because even though choosing the right module (shareable folder), the loaded module is the one on the app folder)