Intel Mac :: Moving Folder On Windows Server - System Password Asked

At work I work on a mac, but our files are on shared windows network drives. There's one particular drive which causes our mac users problems. It doesn't happen on all folders/files, but on some of them the following happens.�I try to move a folder to another location, but then suddenly my mac asks for the system password. I fill that in and press ok, but nothing is moved. The folder is still in the same location. This only happens om certain folders and the funny thing is: when I try it on of the following days, the problem for that folder is gone and I can move the folder to the folder I wanted it to move.

But in the meantime there are other folders which can't be moved.�Support - being not into Mac strangely enough - says it's a Mac problem and I should update to 10.7. It happens only to me and my colleagues at the place/office where I work. The windows server is at some place else so everything goes via internet.�I keep insisting it's some kind of permissions thingy. Support says it's a Mac thing. What can be the problem and how can I make it clear to them that is isn't a mac thing?