Cannot open MS Project file on Livelink via Excel

Question

I am building a tool that allows a user to open and edit an MS Project file that I am going to be storing on a Livelink site. I've done this before where I edit an excel file in Livelink and taking the WebDav link and converting it to a file location: WebDav Link - http://livelink.com/csdav/nodes/... File Location - \livelink.com\csdav\nodes...

I am doing the same exact thing for the Project file, but cannot open it using the file location. Anyway around this?

Code:

    Set appProj = CreateObject("Msproject.Application")
    appProj.ScreenUpdating = False
    appProj.FileOpen proj_file 'proj_file is the file location
    appProj.Visible = True
    Set aProj = appProj.ActiveProject
    aProj.Activate