Lately, when I try to extend a site and create a content DB using WSS, if I select "Network Service" as the owner of the application pool it gives me "Server Error in '/_layouts' Application" Runtime Error after I successfully extend the site and try to login for the first time. It does redirect to templatepick.aspx, but that page never shows up. Can anyone help me fix this? I've tried reinstalling WSS to no avail.