problems with word 2007, footnotes, endnote?

A co-worker is using Word 2007 in compatibility mode. She was working in
a particular file using Track Changes for several weeks. Then she
installed Endnote and she noticed that Word 2007 kept freezing when she
was working with footnotes.  

One time when the problem surfaced, she saw an error  message and
thought she saw the word "Endnote" in the text of the error. She
uninstalled Endnote and has not had a problem in that file since.

I cannot reproduce the problem. I am working in a copy of the file that
gave her problems and have deleted and inserted footnotes successfully.

Are there known problems with endnote and footnotes in word 2007?

She is using Office 2007 and Endnote X.