Thank you for the quick reply,
I have my site under the directory a which is a CMS based program named "phpBB". I tried renaming my .htaccess but nothing happening getting same error even for my social site at "hangout.vaylayz.co.cc/j/".
About log it is filled with the error given below,
"[Tue Mar 15 03:12:58 2011] [error] [client 188.54.97.136] File does not exist: /home/vaylayz/public_html/500.shtml"
which I think is for the 500 error page.
Moreover, I can't access the cpanel from this address "vaylayz.co.cc/cpanel" but it is working from heliohost website. So what should be the solution?
Regards