dreamhost not writing htaccess

I installed WP on Dreamhost such that the wp files are in a separate folder such that the blog url is mydomain.com while wp is at mydomain.com/wp

as with initial installation, the initial blog url will be at mydomain.com/wp while wp will create the .htaccess file within /wp

but when i change the blog url to just mydomain.com, wp can’t create nor update the .htaccess found in / folder even with permission set at 666. i can edit by hand but well, wp is suppose to make life easy…

anyone has a solution or similar problems?

thanks.