If the list language is Ukranian, the character set should be utf-8. One potential issue is that the web server can be overriding this with its own Content-Transfer-Encoding: header that specifies something other than utf-8.
I am still having some trouble understanding encoding and archives. You were correct that the webserver was overriding the utf-8 encoding on the archive pages, so the contents pages look great now.
What I'm still having a problem with is the display of some messages on the archive pages. Some of the messages appear correctly in cyrillic, but some of the messages do not. The archive menus and headers, etc, appear with the correct character set - it is just the message itself which in some cases appears as gibberish. Looking at the html source of the archive pages, it seems like the message content is inserted into the archive page with <PRE> tags? The list administrator claims that when the emails are sent to the list, they all appear with the correct character set. I am wondering, though, if the problem could be the the email programs of some list members are setting the character set differently such that it is not getting through to mailman.
Sorry to ask such a vague question, but I'm just trying to get a handle on how messages with different character sets get into the archive pages. What factors could cause them to be displayed with the incorrect character set on the archive pages?