Hi,
On which platform your blog is hosted…windows or Linux?
If Linux then add this in htaccess:
# BEGIN WordPress
<IfModule mod_rewrite.c>
ErrorDocument 404 /index.php?error=404
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress
If there no htaccess file then you can create it inside root folder of your domain..
If your domain is hosted on Windows then do this:
1. Create the file wp-404-handler.php in your base WordPress folder. (you can also download it here).
2. Set your sites 404 page to point to the wp-404-handler.php url. Most control panels at web hosts allow you to do this. If you’ve got the option to select between FILE and URL then choose URL.
3. Go to Options -> Permalinks in your WordPress admin page, and choose an appropriate structure for your links. Choose Custom with this pattern:
/%year%/%monthnum%/%day%/%postname%/
That’s it!
Thanks,
Shane G.