might need to check that your server meets the requirements to run jamroom:
Docs: Requirements
https://www.jamroom.net/the-jamroom-network/documentation/getting-started/774/requirements
Sounds like either your server is not able use the 'symlink' function to move the filesystem around.
What happens when a new module is installed via the marketplace is that the old version is moved to its version number and a new version is downloaded.
Ask your server company to check to see if your server is able to do that.
If its not possible, then the way around it is to not use the marketplace for updates and installs and download the files from jamroom.net and upload them to the server.
That way will avoid the need for symlinks, but its much more of a hassle to keep your system up to date.