Elements in Variables & Functions Modules cannot be added/modified in a Multi-user project

[Anas_FAISAL]

Hello,
I set up a Multi-user project in a local server. afterwards I accessed this projects through 3 other client computers. Two of these clients are able to edit this project normally.
The third client however cannot add/modify Elements in Variables & Functions Modules only. Whenever this client tries to do so, a "parameter is wrong" error appears. 
I realize that when a certain module is locked be a client, other clients cannot modify that module. This is different, It happens even when the client in question creates a new Multi-user project and no other client has accessed this new projects. Other clients that access this new project afterwards are able to modify the project normally.

What could be the problem? 
Thanks in advance.

[felixst]

Dear Anas,

are all clients using the same zenon Version?

Regards,
Felix

[Anas_FAISAL]

Dear Anas,

are all clients using the same zenon Version?

Regards,
Felix

You were right. The client in question was using an older version. 
Many thanks.