"start with mongrel" doesn't work, but "ruby script/server" works. Why?

In InstantRails:

I click Manage Rails Applications, check Shovell, click Start with Mongrel, visit http://localhost:3000, click Submit a new story!, type login information, click login, the Ruby Console Window closes, I can't login and Firefox outputs Connection Restarted.

or

I click Open Ruby Console Window, type cd Shovell, type ruby script/server, visit http://localhost:3000, click Submit a new story!, type login information, click login, the Ruby Console Window doesn't close, I 开发者_如何学Gologin and Firefox outputs the form to submit a new story.

I'm wondering why... Do you know?

UPDATED:

log/development.log -> http://pastie.org/802310

stack trace -> http://f.imagehost.org/view/0500/mongrel

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Impossible to say without more data. Check your error logs -- look for log/#{RAILS_ENV}.log (probably log/development.log in your case).

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Edit: Additional info was provided by the OP, so I"m updating the answer.

This looks very much like the notorious Rails-not-playing-well-with-MySQL-on-Windows problem. See here and here for more info, and try downloading the file here for InstantRails.