In the E463 specifications table, sampling format is specified as:
"Original File Format (16 bit, stereo)"
Uh, oh, I smell a proprietary format.
With any luck, you may be able to import the file into Audacity (or whatever) as a raw audio file (16-bit linear, interleaved stereo, 44.1kHz), delete the proprietary header info (which will sound like noise), and write the result as a proper WAV or AIF file. It's not that hard to do, but if you need to convert a large number of files, then it gets tedious.
Andy's good comments still apply.
All the best -- pj
P.S. I took a quick look at the manual. The "Original File Format" probably stores the key zone information as well as the digital audio samples.