The way I go about it collaboration is this: convert the project to a central model, save it, close the Revit file. Then copy and paste the central model and the new pasted file becomes the local model automaticly. So rename it and start working from it. If this doesn't work then the issue is with your shared folder and I would tell your IT guy to figure something else out, either adjust permissions or create a shared drive.
The definition of insanity is doing the same thing over and over again and expecting different results