cannot register my theme

I bought the theme called Backpack Traveler from MiKaDo. I haven’t used the theme till now. Now when I am trying to install the theme and enter the purchase code to register my pack. The register theme button is not working.
When I enter the purchase code and email id in the field and press register the “please wait” is visible but the registration is not getting completed.I wanted to know why am I not able to register my theme copy.
Thank you
Desiya priya Nivas