Hi C. Mourad Jaber,
If you want to deploy process definition from inputStream. You have to set a name for this InputStream. And this name must end with ".jpdl.xml". So jBPM 4 could know how to deploy it.
Your problem is the name did not end with '.jpdl.xml'. So jBPM 4 did not know how to deploy it. And just store inputStream as a plain blob.
But the error information of jBPM4 is strange. We should review it and let it report the correct information.