Creating a local Game server (not that type of game server)

Hi, i work on a game center,
And online games require update periodically..

so i need to create a server where i can store all the latest update.
And the users can sync the up-to-date game folders them through a shared folder.

There's a catch,
The server must be running XP.
Because each game has its own updater, and i can't run those updater in ubuntu or other linux distros.
(I'm aware manual update exists, but it requires user to modify the game folders, it's too risky, so it's not an option)

So far i've been using XP combined with Virtual Box running ubuntu,
why? well for unknown reason XP limits sharing option to 10 PCs, anything above that and it will disconnect the server.

Ubuntu does not have this limit, so the ubuntu v-box is used to create linux-based sharing mechanism so that the clients don't encounter limitation problem..

At first i thought it would solve the problem..
But occasionally XP still get disconnected for unknown reason..
Re-starting the lan doesn't solve the problem,
it always requires a restart to fix it...

So i'm looking for another alternative, maybe another sharing method...
Any idea?