If you have Mathcad 15 and prime installed on the same PC you should be able to convert. Note that your Prime license entitles you to license Prime and Mathcad 15.
I see you assisted another person to convert a file. Would you mind doing the same for this one? I have Prime 2.0 but I can't run Mathcad which I could probably install an older version for but Mathcad doesn't work on my newer Windows platform except in some emulator mode which I tried and it didn't work at least not for me.
Here you are. I hope it works.
The converter had the following messages:
1. The Data Import Wizard is not supported in the current version of PTC Mathcad. Your data was imported using a suitable File Access function. Unless specified, the accuracy of the results is not affected.
2.Plot labels are not supported in the current version of PTC Mathcad. Use text boxes to label your plot.
For further files you can follow the below procedure to convert the files
Users can also launch the converter using one of the alternate options below
From <Mathcad_Prime_Install_Dir>\ WorkSheetConverter.exe
Select Add Worksheet > Select the desired worksheet/s to convert > Convert.
Note:- Each successful conversion creates a new worksheet with extension *.mcdx in the same folder as source file.The source worksheet is not modified.
Also, you can refer article CS22570 for more information.