Msg#: 3655691 posted 8:53 pm on May 21, 2008 (gmt 0)
I can explain but probably not help, since "helping" may require that you modify the WordPress code...
Your mod_rewrite code says:
IF the requested URL does not resolve to an existing file AND IF the requested URL does not resolve to an existing directory (or folder, if you prefer) THEN Rewrite the request to WordPress at /blog/index.php
Therefore, if you request a non-existent page, the request will be sent to WordPress, and it is up to WordPress to determine whether or not that page exists and to handle it properly.
Evidently, WP is not handling it properly (at least not on your installation). I don't mess with WP, so there may be some option you can set somewhere that causes it to check for invalid "WP post" requests and to return a 404 if needed -- I don't know.
Msg#: 3655691 posted 5:23 pm on May 22, 2008 (gmt 0)
Wordpress should handle 404s just fine - and yes it is handled internally, but I always get a valid 404 if I ask for a non-existen page. A lot of effort has been put into dupe content and improper header issues.
If you are getting an absolute blank page, that to me sounds like you have a PHP error and you have error reporting off or WP does its own error handling and displays nothing. Unfortunately, WP has no system log so it doesn't tell you what errors might happen (only on plugin activation).
Do you have any plugins that fire on 404? Try disabling all your plugins and requesting a non-existent page.