Software :: File Sharing - No Appropriate Access Privileges?

I'm having trouble accessing files and moving folders on a shared drive. When I try to open or move a file, it says "The document "X" could not be opened. You do not have appropriate access privileges. To view or change access privileges, select the item in Finder and choose File > Get Info." and when I try to move a folder, it says "This folder cannot be moved as you do not have access to some or all of the items." The IT (who is not trained to deal with macs) says I have full permissions for our shared drive and that the problem is with my computer. So I followed the instructions in the warning box.

However, in the Get Info for the file, it says under Sharing & Permissions "You can read and write". In my System Preferences, both my user accounts have the administrator access box checked. In the Help section, it gives instructions along the lines of "in the Sharing & Permissions section, click the lock next to your name to change permissions" and also "in the action (gear) section, select the option for permissions that you want". Trouble is, there's no name and no lock in my Sharing & Permissions box. There's also no 'action (gear)' option anywhere. When I click on the triangle next to Sharing & Permissions, it literally just says 'You can read and write'. There's no other option or information.