I contacted customer support and they directed me to: http://support.ehostpros.com/hd/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=137

Part of what it says to do is set the permissions to 755. How do I do this?

Your FTP program, or a control panel that the host lets you use are the two most common ways. You can also shell into the account with telnet and set permissions but the host has to allow telnet connections. Using your ftp program is very easy. See it's help files for chmod.