FYI, for good measure I've also tested DiapDealer's KindleImport plug-in on a 64-bit Linux machine (with Python 2.7.3) and didn't get any
pathof warnings.
I.e., this might be a 64-bit Windows Sigil build issue, a Windows 8 issue or a 64-bit ActivePython 2.7.8.1 issue.
@DiapDealer: Since the plug-in definitely works, maybe you could simply readme this behavior and move on to more interesting things instead of debugging Windows-only bugs. :-)
@Sigil 0.7.7 Windows beta testers: Can you please test DiapDealer's
KindleInput plugin on your machine and report back whether you're also getting
pathof warnings at the end? (You can use this
.azw3 file as input file.)