500 Internal Server Error Happening Days After Installation

hello,

i have a few sites with elgg installed on them via softalucous and after a few days most of the sites have errors on them. Here is an example of what is happening on my sites: http://cigaretteshere.biz

After installing elgg i have changed literally nothing so don't know what could be causing this error. when i try to login to the elgg account i get a 500 internal server error. anyone know what could be causing this?

i talked to my hosting company and they said it was because i changed something with my htaccess file but i have changed nothing at all to any files or anything.