Thank you for your post.
The Web folder is strictly for Instant Web Publishing displaying container objects stored as references. This is not the same for FileMaker Pro peer-to-peer sharing. In this case, the entire file path is read, and if not found, FileMaker will tell you. It will not look for a default location.
In order to see container objects stored as references across the network, the other users must mount the volume where the files are stored. For example, if I wanted to store a file as a reference on a Macintosh computer, I may put the file in a public .me (.mac) account and set the reference there. Then, I would ask others to access the public .me account prior to opening the database file. If I needed it for Instant Web Publishing, I would put the file in the Web folder.
Originally, I thought you came across an undocumented feature, but no matter what steps I took, I could never display a container reference via FileMaker Sharing unless the reference was either located in a shared drive, or embedded in the database itself (which I think is your case).
One way of checking to see if your file is referenced is to create a calculation field that references the container field. If it shows just the file name, then it is embedded. If it also contains the full path name, then it is referenced.
Been a while since I've been around here... apologies for the late response.
But thanks! Everything working well now.