I have a problem!

When I make a research in google, I return an internal error in the browser(error 500).

I have to go to the folder ' www' ,and delete the file htacess to resolve the problem. but passed some time the problem appears again, because the file htacess automatically creat's it self again and i have the same problem again.
Somebody knows some way to resolve the problem pemanently

I excuse me for my English, but i need some help.