Changes to the distribution list membership cannot be saved

From Exchange 2003 to Exchange 2010 we shifted mailboxes then we have begun receiving information from Exchange 2010 users that they could no longer maintain sharing catalog which they hold.
On Exchange 2003 User did not face any problem regarding maintaining their sharing catalog.
Once an Exchange 2010 user tried to amend single or many sharing catalogs they hold, they would get the below error message.

Changes to the distribution list membership cannot be saved. You do not have sufficient permission to perform this operation on this object.
We had a some of Outlook 2007 SP2 users’ information that they were receiving the error message,

The Delegates settings were not saved correctly. Cannot activate send-on-behalf-of list. You do not have sufficient permission to perform this operation on this object,
While they attempted to insert or eliminate a Delegate.
Please let me know the procedure to solve this issue. It would be helpful for our user to fix these issues.
