The first troubleshooting step would be to check the resultant permissions on that folder for the user. Right Click on the folder and go to the security tab, click advanced, then click effective permissions. Click select and enter the user's name. Once you accept it will show you what the effective permissions are for NTFS. Also remember that there are two sets of permissions for shared folders. The best practice is to always configure share permissions as "Authenticated Users" in an AD environment. This way you don't have to worry about permissions conflicts.