Can't connect to GMail to Sync

When my iPad is connected to iTunes, I'm trying to Sync Contacts with Google Contacts. This requires me to logon to Google. When I do so, iTunes tells me "the Google ID or password was incorrect". I know this is not true - I can easily logon to gMail on the same computer. Why can't iTunes connect to Google/gMail?

To get around this obstacle, I tried syncing Contacts with Windows Address Book. This process seems to work, but then I can't find the Contacts anywhere on the iPad, not in the App called "Contacts" nor in the contacts in Mail. Where are they?

All help appreciated.