It sounds like it is just a security issue with permissions or you have multiple mapped drives with different log in credentials to the same computer. Are you mapping your Q: drive to a file or to a drive? If you are mapping it to a file dont only check the NTFS Permissions but also the Share permissions, because the default share permission is read. Maybe its a dns problem but, just check for host A records just to make sure. I hope i could atleast help you with places to look, let me know if you are still having problems.