Internal Server Error –

My blog is down. Earlier I changed my password but it was not changed in wp. admin. I have now changed this now and no longer get Error establishing a database connection message but now when I try to get onto the blog I get the following message:

Internal Server Error The server encountered an internal error or misconfiguration and was unable to complete your request.

I checked in error logs in my hosting account and the main issues came up:

line 1: host: command not found[Fri Feb 11 00:27:52 2011] [error] [client 209.85.238.215] Premature end of script headers: /var/chroot/home/content/a/r/c/archoni/html/blog/index.phpZend Optimizer requires Zend Engine API version 20021010.The Zend Engine API version 20050606 which is installed, is newer.Contact Zend Technologies at https://www.zend.com/ for a later version of Zend Optimizer.

[Fri Feb 11 00:28:37 2011] [error] [client 114.111.95.132] File does not exist: /var/chroot/home/content/a/r/c/archoni/html/robots.txtZend Optimizer requires Zend Engine API version 20021010.The Zend Engine API version 20050606 which is installed, is newer.Contact Zend Technologies at https://www.zend.com/ for a later version of Zend Optimizer.

I emailed hosting support they suggest I contact Zend and get older version.

I thought of using backup of the database that was made Tuesday before the site went down or any plug ins were added.

I don`t want to try anything if there are any better suggestions.

If anyone can help I would be grateful.

Thanks in advance