In Internet Explorer 6 there is an "invalid argument" JS error if you have an empty section in a course.
This line of section_class.prototype.process_section is the culprit:
With an empty section this.content_td.childNodes seems to (sometimes?) only have 2 items in it - hence this.content_td.childNodes is undefined and insertBefore gets upset. At first I thought this only happened if you had a course in topics format, but it seems to sometimes also happen in weekly format?
Assuming we want the resources list inserted just before the add resource/activity drop down lists and that the div containing these select boxes is the last element in the section, maybe something like this would work instead?