Error on creating a new view Or joining a new project   

I'm facing a strange error when I tried to create a new view or joining a new project it says:

Error reading VOB Objects from the ClearCase registry.

This is happening only from the client machines. When I do the same action from the CC server it doesn't show the same message and work perfectly.

Can any one help me why this message appears? The message error is attached as image.

Thanks In Advance

Thanks Dilip for your response.

I tested the region on the server and the client, both give me the same value "CCRegion".

I'm sure that the registry is connected. Because I can make some activities like deliver and rebase stream.

But if i tried to retrieve all the VOB Objects by the project explorer or by creating a new view, I'm getting the same error message.

Any other suggestion?

Thanks Tgefen, and here is my answers for your questions:

1- I didn't change any configurations recently. The last thing I have did is removing one VOB from a long time.
2- I checked the client logs at "C:\Program Files\Rational\ClearCase\var\log" but i didn't find useful information.
Also I didn't know which log I should check for the server, since there is a lot of logs on the server side.
3- make view is working fine in the command mode, because it will not list all the VOBs like in the windows mode.

I appreciate any new suggestions from you.

Thanks Dilip, you are guiding me in the right way.

1- I have set the primary group variable.

2- I have made a rgy_check -vobs
The result was "91 total registry errors/inconsistencies detected."
All of them was the same error
"rgy_check: Error: This VOB tag has no VOB object with the same UUID"

I have made a rgy_check -views
The result was "704 total registry errors/inconsistencies detected."
All of them was the same error
"rgy_check: Error: This view tag has no view object with the same UUID"

91 VOB and 704 views is the total number of the vobs and views I have in my system.

3- These errors appears on all the client machines, the only machine that doesn't have these registry errors is the server machine.

I have two questions now:
1- What could happened to destroy all my vobs and views on the client side?
2- How I can fix this issue?

Thanks In Advance

I still can't figure out the solution for this problem. I can't unregister all the views and vobs.

I have done one exercise by comparing the UUID for one views and its corresponding view tag and I found it identical.

I believe that there is one wrong action has been done. (ex. creating a new view in a wrong way) and this action caused all this miss.

Can any one help me in getting another solution rather than unregister all the VOBs and views?

Thanks In Advance