Hi Fast,
Real weird problem!

Double check that you have correctly configured Cumulus
in menu Configuration --> Internet --> Files, you could have
some mixed files (2 different files, but same REMOTE Filename??).
I suspect that your processing of the file
system.htm is incorrect,
as we don't see any system.htm page on your site... but
index.htmis the system page.
Hope this help,
Regards,
Jacques