What jamroom does when installing skins or modules via the marketplace is to use a symlink to link to the most current version.
When you install jamroom the file system will look like this:
/modules/jrCore/*
but then when you update core or any other module or skin via the marketplace, it will change the file system from the above directory being a real folder, to it being a symlink to the latest version.
In the file system you will have:
/modules/jrCore
/modules/jrCore-version-5.2.3
/modules/jrCore-version-5.2.4
/modules/jrCore-version-5.2.5
...
and the symlink on /modules/jrCore will point to the highest version.
If you're system doesnt support symlinks (maybe because its windows
Wamp) then you might try not using the marketplace for updates and just download the modules from jamroom.net and upload them to your system.
This should get around the need for symlinks, but you'll probably run into other issues. Jamroom does not run on windows.
Docs: "Requirements"
https://www.jamroom.net/the-jamroom-network/documentation/appendix-about-jamroom/774/requirements