This is a really strange issue. It seems as if all accounts except for Domain Admins cannot write to the domain controller. It happens that the file sharing is done by the domain controller.
When I check for Effective Permissions, it looks good, in otherwords the user can read/write/delete and in some cases the user is the owner of the directory.
Since these issues seem to be only on this domain controller my thoughts are that it has to have something to do with the security settings on this machine, or the local security policy. What should I check to ensure that users can write to shares on the domain controller?