I am already a contributor but the password on Google Code doesn't work
What do you mean when you say the google-code pwd does not work?
1. Can you log into google?
1.1 No. Troubleshoot the problem using this google help page.
1.2 Yes. Log in and go to page http://code.google.com/hosting/settings. The 'googlecode.com password' which is listed on this page - is this the pwd that you have been using? Try regenerating this password if it does not work. Also when logging in through SVN, please note that the username is not the full e-mail address if you are using a gmail account, but just the first part of it - in case of 'email@example.com' - just 'myname'