I can tell you are stripping your code down to bare minimum to put on the forums, and that is fine and quite understandable, but we are missing a lot of valuable information. If you could please include your headers, we can see how you are defining your signals, slots, members, etc., which will help us understand your code better, which will allow us to help you better.

That being said, I just noticed a discrepancy in your code.
Qt Code: 
  1. myProBarDialog = new proBarDialog(this);
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as compared to your apparent class name, "pBarDialog". You will need to instantiate with the appropriate class name:
Qt Code: 
  1. myProBarDialog = new pBarDialog(this);
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Aside: I also noticed you are not deleting your "mProgressBarDialog". By setting the pointer to NULL, you are changing where it's pointing, but not de-allocating the memory you grabbed when calling new. The memory leak would be small, but it is still a leak.