Zoho Mobile on a Kindle

Zoho Mobile on a Kindle

I have setup a Zoho account on my PC but I cannot Sign In on my Kindle. I have heard that Zoho will run in a Kindle browser but after I type in my user name and password and navigate to the Sign In button nothing will 'press the button' neither the CR on the Kindles keyboard nor the enter on the 5 way button. The sign in button below for Google apps works ok but responds with an authentication error as I have no Google apps account.
regards, Bren