Yes. You haven't installed the extension mozrepl in your Firefox.

However, although installing it will stop the crash, it won't load your cookies with the current Firefox. I have searched for hours, and not found any Perl module that can load either Chrome 49 or Firefox 45 cookies. (Chrome cookies now have their values encrypted.)

I installed https://addons.mozilla.org/en-US/firefox/addon/cookie-exporter/, exported my Firefox cookies to cookies.txt, and tried reading that with the old HTTP::Cookies::Netscape->new(file => $CookieFile, autosave=>0). It doesn't work right off, because cookie-exporter doesn't write out the header indicating the file is a Netscape cookies file, so HTTP::Cookies::Netscape won't read it. (It's vital to use perl -w when trying HTTP::Cookies::Netscape, or else it won't tell you why it fails.)

So, first add the line
# Netscape HTTP Cookie File to the file, and then HTTP::Cookies::Netscape can read it.

The correct documentation on the Netscape cookies file format does not appear to exist anymore, only documentation of the format of the individual lines. As a result, we have a new generation of tools that say they're using Netscape cookies format, but aren't.

Alternately, you may have to just find the user's cookie sqlite db, open it via DBI, and query it for the cookies you want.