Server :: Ubuntu Based Network Drive Drops Out After 2 Mins With USB Adapter Not For LAN

I have an Ubuntu-based fileserver, which I have set up and works fine for 5 computers (Windows & Linux based). I have one computer, on Windows, which when I map as a network drive it works and I can transfer small files using the USB adapter. However, when copying over a large file, after 2 mins or so it comes up with the error "Specified network name cannot be found". However when plugged in using Ethernet, it will work fine.

What is even stranger is when I set it up as an FTP server rather than SAMBA, it will happily transfer a 4gb file on the USB adapter, which possibly knocks out driver issues (I have tried 2 different drivers, am currently using Linksys one from website - WUSB300N) AND perhaps the issue lies on the Linux server side with setting up the SAMBA server? However I do have another one of these adapters that works fine, but it is on WIN XP HOME with a custom network logon script (as HOME won't remember passwords after restart). BUT it does work on another computer with XP PRO as network place, so I tried network place on this one, and it still doesn't work.......