[wp-hackers] Error in core problem

[rajasekharan]

Hi all,

While working on my theme, a new error seems to have crept into the 
wordpress core (or somewhere else). Not sure what I did wrong, but I 
keep getting the following error:

Call to a member function wp_rewrite_rules() on a non-object in 
C:\apache22\htdocs\blog\wp-includes\classes.php on line /145

/I was editing the header.php file and a stylesheet. I have not touched 
any of the core files at all. What could be the problem?

Raj Sekharan