"Use of uninitialized value in substitution iterator at /Users/sbr/Library/Application Support/TextMate/Bundles/Markdown.tmbundle/Support/bin/MultiMarkdown.pl line 1582, <> line 1."
This happens if the footnote is referenced but the declaration cannot be found. Footnotes with only one word[^test] or only a link[^test2] don't work.
I have had no problems with using single word references, e.g., [^note] and then etc. However, there are two things to remember with multimarkdown footnotes.
First the footnote text [^note]: text should be in the same section that the note is , i.e., not in another chapter. Second, each [^note]: text needs to have an empty line to define it. So:
The footnote command does not recognize 3 or more spaces after a line as a hard break.