Thats what i was talking about in my first answer.
Did you look at the xml file your posted? Its the protocol of the conversion and contains the error message
"Mathcad 15 M010 or a later version is necessary to run the converter. Please install the latest version of Mathcad 15 and then restart the converter."
You need to download and install Mathcad 15 to be able to convert files from real Mathcad to Prime.
If you bought a license for Prime you are also entitled to use Mathcad 15.