Message I Keep Getting After Away From PC For An Hour

Whenever I am away from my computer for a while and the switch user screen comes on where you have to click on the user name comes up to get back to my desktop I get the following msg comes up

Here are more details:

Here is a more detailed msg of this issue:

See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.InvalidOperationException: Unable to ping because a network connection is not available.
at Microsoft.VisualBasic.Devices.Network.Ping(String hostNameOrAddress, Int32 timeout)
at Microsoft.VisualBasic.Devices.Network.Ping(String hostNameOrAddress)
at MSE_Update_Utility.Startup.tmrConnectionCheck_Tick(Object sender, EventArgs e) in D:Program FilesVisual Studio 2008ProjectsMSE Virus Signature Update CheckerMSE Virus Signature Update CheckerForm2.vb:line 142
at System.Windows.Forms.Timer.OnTick(EventArgs e)
at System.Windows.Forms.Timer.TimerNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)