[bullfrog]

This is a repeat of the error message for all to see in case it gets fixed quickly:

Can't write template cache in the directory: /home/antiphon/antiphonic.com/store/templates_c.
Please check if it exists, and have writable permissions.

I have not seen this problem, but to check out what the error says, FTP into your site, or use whatever file manager your ISP provides, and make sure that the directory /templates_c still exists. It may have been erased or may be corrupted. If it is there, check permissions using whatever method is available to you. Most FTP programs will tell you permissions on files and directories. Look for a 777 or 757 permission.

If the directory is missing, make a new one and give it 777 or 757 permission. If the directory is there, but permissions are gone, reset them.

Best wishes with this. Your ISP may be able to help, as this is not necessarily X-Cart related.