If the Digital Rapids writes a PCM file with .pcm extension it is most likely a "raw PCM" file instead of a "PCM WAV" file. Encore, like most other applications, will accept only the .wav variety which not only has a different extension, but also a different structure.
Failing an option to write a real .wav file directly, you could check the "Tools" section at
VideoHelp for a utility to convert from .pcm to .wav. Such a conversion will be lossless.