I've recently imported a number of notebooks successfully from Evernote ENET export files. I had one notebook that stalled during import, and was able to isolate a single note that fails. I've moved that single note into a separate notebook and ENET file to isolate the problem. The log file contains multiple instances of "Unsupported note tag: span". I'll attach the log file and single record ENET file.
This is low priority as it is only one record, and I can simply copy it manually if needed.
The ENEX file was corrupted, which is why it couldn't be imported. In fact, even Evernote cannot import it (it results in a empty note body). Was that file generated by Evernote or by some other app?
In any case, I've added a small hack to handle this issue in case it affects other existing notes.