404.php not implemented with different permalink structure

[sluggo]

When you switch the permalink structure from "Default" to one of the other choices, it stops catching 404 errors and serving 404.php--even if you go directly to index.php?error=404.

Works on my system. Try disabling all plugins, switching to the default theme and trying again. If that still doesn't work, then can you install dump-env [1] and give us the output?

[1]: ​http://dev.wp-plugins.org/file/dump_env/trunk/dump_env.php

Works for me as well.

Custom structure in use: ​http://www.viper007bond.com/archives/2006/04/02/weathericon-v3-beta/

404's working: ​http://www.viper007bond.com/foo/bar/

Reopen if it still doesn't work with all plugins disabled and such.

I changed to default theme, disabled all plugins, same problem. I installed the dump plugin and posted the results to ​http://www.unknown.nu/temp/dump.html.

I just posted a report on this bug to the forum, at:
​http://wordpress.org/support/topic/68607

It includes steps to reproduce it as well. My dump_env feedback, which I created with all plugins deactivated and the default theme selected, is here:
​http://mikelee.org/dump_env.html (view the source of page)

To see the 404 error I'm currently receiving, visit:
​http://www.mikelee.org/404

Currently, the plugins I'm using are:

• ​Yahoo/MSN Style Smileys
• ​Links-NoFollow
• ​Unfancy Quote

Please let me know if I can provide any more info. From what I've seen at the forum, there seem to be a number of users facing this bug. If there's any way I can persuade you to raise its priority, please let me know! Thanks!

Note: This user resolved his problem in the Support Forum:

My sysadmin looked into the problem, did some research, and discovered that FastCGI was causing the problem. The solution has already been documented here on this forum, in the thread ​http://wordpress.org/support/topic/67416

It appears that the solution is in #2628, which is marked fixed.

I'll close this as a duplicate of that bug, since it appears that is the fix.