You have a stray < character in your header file.
Post your header.php code in a pastebin http://wordpress.pastebin.ca/ and post the URL here
Hi
You had some bad code in your header.php I pasted the corrected code here http://wordpress.pastebin.ca/1376034
There had been an attempt to customize the <title> in the <head> section. That code was all messed up so I removed it and pasted in the <title> from the default WordPress theme. You can update it as you like.
I like using the All in One SEO Pack plugin as it automatically generates context-sensitive page titles on each page and post.
when You update it,you mean copy and past it in my header in my editor
Hi – take the code I pasted in the pastebin and replace the contents of header.php with that code. Before you do that make a copy of header.php as it is now, in case I made any mistakes.
Save that pasted in code as the new header.php. Then upload it to your webserver using FTP. After you do so you can make any changes you care to, to the code I fixed. The first step is getting your site working correctly with a more generic header.php