ok so ensure that there is no white spaces for
ErrorDocument 400 /forums/400.php
ErrorDocument 401 /forums/401.php
ErrorDocument 403 /forums/403.php
ErrorDocument 404 /forums/404.php
ErrorDocument 500 /forums/500.php
&
# Send hardcoded ipa scores to arcade instead
RewriteCond %{QUERY_STRING} act=Arcade [OR]
RewriteCond %{QUERY_STRING} autocom=arcade
RewriteRule ^index.php arcade.php [L,QSA]
there should be no spaces before or after
you dont need to type anything for the errors
as long as you have this mod active and fopr example
if you type
blahblah.php it will show the appropriate error
the redirects are auto
see if you type
http://mydomain.com/~tcmasorg/forums/
it works