I have been fighting SMB shares on Mac OS since upgrading to Mountain Lion (I skipped Lion) and I think I have the situation figure out at least in my case.
First Opportunistic Locking needs to be turned off in Windows 7. It does not appear that Mac OS supports it and this is why my connection got disconnected.
In the regestry at, [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\LanmanWorkstation\Paramet e rs] add this, "OpLocksDisabled"=dword:00000001
Now for the SMB shares for people using the Server App. The Server App. is where you setup shares but I think there is a bug. In my case the Server App. was not actually turning on SMB and/or AFP services for the users listed in the server permissions. I had to go to Sharing under System Preferences then select the share I want the service to apply to then select Options. I found that the SMB and AFP services were not enabled even though they had been set in the Server App. Once I enabled them all was as it should be.
MAC MINI SERVER (LATE 2012), OS X Mavericks (10.9.1)