[Mailman-Users] Bug in the public HTML pages

[iMug]

I have created four Mailman mailing lists associated with my organization's
domain name through our web-hosting provider's cPanel (ie I do not have root
access to the server to try to fix problems). One of these lists returns a
"Bug in Mailman version 2.1.9.cp1" error message page anytime a subscriber
clicks any of the submit buttons on the General List Information page or the
Users Specific Options page. IOW, subscribers cannot alter their settings or
email address.

As administrator, I get this same error message page when I click on the
Submit Changes button on the Edit HTML page for either of these two pages
and my changes are not made.

I don't know whether it's coincidence or cause-and-effect, but I believe
these bug error message pages started to appear after I had been editing the
html of the General List page. *Perhaps* it was after I deleted a large
section of the html code -- the "Subscribing to [list name]" section. But
now I can no longer edit the html to put it back to how it was,  or any
other way.

Is there a way I can fix this problem? If it can only be fixed at the root
level, what specifically do I need to request my web-hosting provider to do
(if they are willing to do this sort of thing)?

My alternative is to close & delete this list and start again, but this
would be very disruptive and I would like to avoid it if possible.

Regards,
Hope Stewart