Bunch of PHP errors

While it doesn't break your site, it sure isn't nice to get these error messages every once in a while...

See the attached screenshot.

#1: not sure
#2: seems problematic
#3: include path issue, thus a server configuration issue. Couldn't you somehow work around this? Drupal seems to be able to include module files just fine, so it must be possible for you as well. Perhaps it's throwing an error because .dtd files aren't registered to be opened with PHP (i.e. the handler set to PHP)? Couldn't you just do something like file_get_contents() instead?

Aside from this relatively minor issue, this module has great potential I think, on niche sites at the least. I don't see this form of navigation on an everyday site anytime soon, even if only for the fairly slow loading time. Thanks! :)