Here's an e-mail I just got from NS:
I am sorry that your website is experiencing loading issues. You need to fix your MySQL connection string within your PHP script. Make sure you are using the local network name for the MySQL database instead of the IP address. If you are using the MySQL IP address, the script will go out to the Internet, then back in the network to perform queries - which produces more latency, and possibly Internal Server Errors or Timeout errors. The internal network name looks something like "mysqlv101" and can be found in the account manager under nsHosting - Configuration - Database Manager.
If you complete the above instructions and your site still errors, your code / overhead may be too robust for a shared hosting environment. If you are comfortable managing your own server or moving your site to a more advanced hosting solution, we do offer VPS packages that may fit your needs.