PHP memory limit is a server issue. Nothing to do with any theme. Even if you set PHP limit to a very high value in your php.ini file or .htaccess file, it is of no use if the actual memory allocated by your hosting server is too low.
If you want to try to increase your PHP memory limit, you can use this article as a reference http://www.thecave.info/php-increase-memory-limit-using-htaccess-apache-php/
The following article from your web hosting company, also suggest that you subscribe a VPS hosting if increasing your memory limit does not help.
You hosting company’s article also suggest that you deactivate all your plugins to see if there is any plugin conflict.
The .htaccess file in your WordPress installation (can be found in same location as wp-config.php) is automatically created by WordPress and by default contains only WordPress rewrite rule. Creating another empty .htaccess file does not help at all. A .htaccess file is for configuring Apache web server, nothing to do with theme. Here’s a good related article http://en.wikipedia.org/wiki/.htaccess
Very sorry, I am afraid that’s all we can help regarding this issue which is unrelated to our product.
If your hosting company is unable to physically help in resolving your issue and can only sent you to read documentation which is meant for a programmer, I truly suggest you hire a competent programmer to assist you in troubleshooting this server issue.