I'm facing the same problem, I tried uninstalling the program and when i try registering my Gmail account it asks for a password (that i think that it should be the mailbox's pass) but it always says that it's wrong. I cannot login on email.nokia.com either with the same user. Tried remaking an account but it says the user it's taken. Changed my mailbox's pass and retried with the new one on the phone and on the computer and same result. I cannot find the "forgot your password" page on email.nokia.com.As a temp fix i registred on the phone with another email address and then added the problematic Gmail account and in this way i can retrieve my emails.
Please tell me how can I login or change the password to this gmail account.