[ic] Unable to edit content in admin menu

[Bryan Zimmer]

I'm running Interchange 5.0.1 on Debian 3.0 and can't edit my catalog's
index.html with the admin interface. When I go to content -> page edit ->
index.html there's a frame on the left side with a list of editable regions
on the page. Between the "header" and "footer" regions only "slot 1" is gray
and usable. When I click on it, it has the content that should be in the
"content" region. At the very top of the content editing page I get this
error in green:

parse_page: no slot number 1 parse_page: no slot number 2 parse_page: no
slot number 3 parse_page: no slot number 4 parse_page: no slot number 5
parse_page: no slot number 6

This catalog was originally from version 4.8.6, recently upgraded. I get
this problem when I drop it unchanged into 5.0.1 or when I replace the pages
and templates with those from the 5.0.1 foundation store.

Does anyone have any insight?
Thanks,
Bryan