This is something that creeps up every once in awhile with some hosts. Generally it’s due to either a permissions issue (possibly you have theme files set to 777 when they should be 755 on your server setup) or possibly your server has Apache’s mod_rewrite configured in a way that flags something in the file. I have a feeling your host is probably going to tell you what the issue is by simply looking at your error log, and there will be a simple solution.
This is searchable archive of our old support forums, which operated from 2012 - 2016. To find out how to get support for your current theme, please visit our support page.