Fixing issue when the 'Play' button is clicked but the file does not exist an infinite loop of error dialogs would appear. We are now checking for the existence of the file before trying to load it.
Fixing issue when the 'Play' button is clicked but the file does not exist an infinite loop of error dialogs would appear. We are now checking for the existence of the file before trying to load it.

OpenMBIR/openmbir,OpenMBIR/openmbir,OpenMBIR/openmbir,OpenMBIR/openmbir