Posting in the Magento forums has been disabled pending the implementation of a new and improved forum solution which should better serve the community.
For new questions please post at magento.stackexchange.com, the community-run support site for the Magento community. We will be providing updates on the new forum solution soon. For questions or concerns please email firstname.lastname@example.org.
Themes built for other editions will not work in Magento Go. Magento Go uses a new, simpler design system. You can do basic design customization in using the Design Settings Editor, or dive deep into custom CSS design. See this Knowledge Base article to learn more about Custom CSS: Customizing the Look and Feel of Your Theme Using the CSS Editor