Ok, so the users have full organization rights to Append and Append to all entity records in CRM that they are trying to track e-mails against like Accounts, Contacts, Quotes, Opportunties, etc.
If you are using the Offline Client, the user should ensure that their Outlook is in Online mode. Sometimes users can be in Offline mode without realizing it. When they have the error, they should check the Outlook button to ensure they are in Online Mode with the Outlook client.
If you do not think the above is the issue, then lets look at one error and see if we can troubleshoot it. It is difficult to provide a 'blanket' response to an intermittent error question.
It is also helpful to ensure that the user has all OS and Office updates on his or her workstation. The user should visit the Microsoft update site and select Custom rather than Express and download all available updates. If Office is not listed on the left side of the web page when they visit the site, then the user should also visit the Office update site to get their Office updates. Once they go through the process then they will be able to view both OS and Office updates from the Windows Update site.
