Looks suspiciously like you're importing id3v2 tags with leading zeroes in the track number fields.

You may be able to confirm it by making two short tracks and tagging one with "id3v2 -T 08 file1" and the other with "id3v2 -T 8 file2", verifying that the two tags differ in the track number tag, then uploading. I expect that the one without the leading zero will work as expected and that the one with will fail as you've experienced. (Can't test this myself, as emplode only runs on Windows platforms)

If that's the case, post it as an emplode bug in the Bugs forum. Roger will know what to do about it (read the value as a decimal integer, rather than as a C-style implicit-base integer).