understanding and debugging the core update process
Installation and Configuration
There's definitely something up with your server - this is not a marketplace or jamroom.net issue.
How it works:
1) Your marketplace module contacts jamroom.net and tells it the versions you are currently running
2) It responds with an UPDATE version, a URL to download the update from and an MD5 checksum of the file
3) the marketplace module on your site downloads the file to a temp location and verifies the checksum
4) it unzips the file and moves it to the versioned directory in the /modules directory
5) It swings the symlink to the new directory
6) It triggers the verify_module event so the updated module can do any work it needs as part of the upgrade process
Let me know if that helps.