Thanks for all the kudos. I think you have actually hit on something here. I will email my networking guy and see what he says. All of the initial research I did talked about auto-disconnect with Mapped Drives, hence the question. AC doesn't work well using Mapped Drives, if at all, so I wouldn't recommend it.
After further research, I found that auto-disconnect (which seems to server no purpose other than to disconnect users who do not log out to make backing up databases safer) can disconnect LAN connections.
As you state, after a certain amount of time based on the -1 up to 65,000 or so, a LAN connection will disconnect. Supposedly, trying to use it again will reconnect it.
While you can change the parameters as you have (actually turning it off) via your command prompt which is recommended, it is actually better, according to my reading, to use the Windows Registry directly.
HKLM\\System\CurrentControlSet\Services\LanmanServer\Parameters
find Autodisconnect and change the value to something like 0xfff. This is generally used for a domain.
I am rather impressed that you found this. It may solve a lot of people's issues.
The only thing I would change since SQL 2005 can use as much memory as your server will take, would be to up it to at least 12 or more to increase your buffer.
