I've tried to install with both 4.25 and 4.26. I get error 500 / Internal Server Error. Since I'm on 1&1, I can't access my error log. I know my way around unix enough to try and debug this myself, but I could use some help deciding where to look.
Reported on Movable Type 4.2

I should probably include that this happens after I click the "Begin" / submit button.
I am having the same problem on a 1and1 server. Any luck resolving this issue? I know I can run CGI because the test works fine and other software on another site works find. I get the error after I hit the go button on the mt-wizard.cgi.
I was able to get past this step by manually editing the "mt-config.cgi-original" as was referred to anothe thread I read here: h**p://forums.sixapart.com/lofiversion/index.php/t64895.html. The mt-wizard.cgi seems to be a GUI for creating the mt-config.cgi file. It wasn't a complicated task and I just saved it as mt-config.cgi and placed it with the other CGI files in my mt directory and it worked.
I am now about to create an account and hope not to encounter any errors. Hopefully it was just something wrong with that file.
I did the same. I think you might also run into problems with the provided path to perl. In the .cgi files, it's /usr/bin/perl, but on 1and1, the path to perl is /usr/local/bin/perl with a symlink to /usr/bin/perl. I had problems with that configuration, but when I changed the dozen or so .cgi files, my issue was resolved.
I do have to say that I feel as though WP is less buggy on 1and1 than MT, but I have to run both.