[Typo3] BE User Permission Problem

[Sandy Matheson]

I have a user who used to be able to edit content elements in the BE
but now when they click the 'pencil' to edit a content element they
receive the following error:

Sorry, you didn't have proper permissions to perform this change.
Reason: ERROR: authMode "explicitDeny" failed for field "CType" with
value "text" evaluated

I have tried to find references to this in the mailing list and
documentation, but have failed to find a reference to this error.

Can anyone point me to why this might be happening.

Many thanks for any help,

Sandy Matheson