No process is associated with this object - webform or vb class

I have been searching on this error and cannot find any solutions that come close to discussing my issue.  I'm not sure if I should be looking to modify the webform or the dll.
I have a simple asp.net web form that calls a vb library class.  They are in separate projects but part of the same solution.
The class file in turn runs an executable with passed in parameters and waits for the exit code which is passed back up to the web form to indicate success or failure.
StartProcess.aspx <==> RunDJClass.vb <==> djengine.exe
All components are on the same server.

It was working fine until last week.  Now I get the following error -

[InvalidOperationException: No process is associated with this object.]
   System.Diagnostics.Process.EnsureState(State state) +493
   System.Diagnostics.Process.get_HasExited() +49
   System.Diagnostics.Process.EnsureState(State state) +339
   System.Diagnostics.Process.get_ExitCode() +15
   RunDJClass.RunDJEngine.RunDJProcess(Object EDIProcess, Object EDIProcessAddress, Object BusinessSeparationId, Object i5EDI) +1157
   FrontEnd.TestDJClass.Button1_Click(Object sender, EventArgs e) +130
   System.Web.UI.WebControls.Button.OnClick(EventArgs e) +108

The error occurs when the web form calls the class RunDJClass library which contains the RunDJEngine class which contains the RunDJProcess routine...

Imports RunDJClass
-----------------------
mRunDJEngine = New RunDJEngine
mRunDJEngine.RunDJProcess(EDIProcess, EDIProcessAddress, BusinessSeparationId, i5EDI)  <BANG>

Can anybody let me know where I should start to look?  Form or vb object? Code posted on request.