NullReferenceException at AForge.Video.JPEGStream.WorkerThread()

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Create a JPEGStream pointed to 
http://trackfield.webcam.oregonstate.edu/axis-cgi/jpg/image.cgi.
2. Call Start() 
3. Wait to receive at least 1 frame.
4. Call Stop()
5. Wait ~5 sec.
6. Go to step 2.

What is the expected output? What do you see instead?
It should run forever capturing a frame on demand.  Instead it crashes our 
application after a day or so.  Because it's an unhandled exception on an 
internal thread, there's no easy workaround.

What version of the product are you using?
2.2.5.0

Please provide any additional information below.

Exception Info: System.NullReferenceException
Stack:
   at AForge.Video.JPEGStream.WorkerThread()
   at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
   at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
   at System.Threading.ThreadHelper.ThreadStart()

Original issue reported on code.google.com by neurot...@gmail.com on 16 Jun 2014 at 7:30