CMS Some users cannot see CMS
 

I have some users who cannot see the CMS when they click the home button below the logo.

They get an error message stating

Your user account may not have sufficient privileges to access this page. Are you trying to edit someone else's post* access administrative features or some other privileged system?
If you are trying to post* the administrator may have disabled your account* or it may be awaiting activation.

I have logged in as a different user and get the same message myself.

Problem is* it's only a couple of them. Everyone else is OK.

Ideas anyone?