.MTP is typically a audio file so you are going to need to convert it you are going to need to find a way to open the file using an application that handles this type of file, then export it in one of the above formats.
Assuming you are referring to the MTP, eg Soundmaker files, that you download from Catooh.
Open Photostory and create a blank project.
From Windows Explorer locate the MTP file and drag and drop it on to the timeline - you should get a message saying the file is being decompressed - click Continue - it will install automatically.