A Certain Plug-In (?!?) for Nero 6

Hi again,

I have a file that I thought for sure my NERO could convert. Apparently not and I was told that these files were created by a MAC (?!?). I can’t verify that last remark so I’ll mention here -

The extension on the file is .sitx and was told it’s an .APE

Is there a plug-in (is that what I need) for NERO 6 to convert?

Thank you