Weird percent symbol "%" generates server error

This is weird..when posting any message that contains the "%" symbol in its title, I receive the following server error message:

Not Acceptable

An appropriate representation of the requested resource /forum/administration/17610-test-100%.html could not be found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/2.2.10 (Unix) mod_ssl/2.2.10 OpenSSL/0.9.8b DAV/2 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server at http://xxxx.com Port 80


The message gets posted, and when I click on it to view it, I receive this error message:

Not Acceptable

An appropriate representation of the requested resource /forum/administration/17610-test-100%.html could not be found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Apache/2.2.10 (Unix) mod_ssl/2.2.10 OpenSSL/0.9.8b DAV/2 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 Server at http://xxxx.com Port 80


I found a similar issue on the Vbulletin forum that indicates this might be a mod_security issue. I've tried the htaccess mod that is located here and it has no effect:

Forbidden and Not acceptable errors? - vBulletin Community Forum

Any help would be appreciated. I initially thought this was a VBulletin problem, and they replied with a cut and paste generalized reply and said it was a VBseo problem.

Hello,

that error might be related to mod_security, if you have it installed. Please try to add this in .htaccess file:

Code:

SecFilterEngine Off
SecFilterScanPOST Off

Hi Oleg,

With those two lines added, I receive a 500 Internal Server Error and the following message:

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, webmaster@xxxxx.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.
More information about this error may be available in the server error log.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

I originally tried these two lines, in the following format:

<IfModule mod_security.c>
SecFilterEngine Off
SecFilterScanPOST Off
</IfModule>

As described in the VBulletin post I referenced earlier. The VBulletin code did not cause any error, and did not fix the problem.

Please check your phpinfo() to see if mod_security is enabled.

Oleg, I see no mention of mod_security in phpinfo. The only thing remotely resembling any type of security is session.cookie_secure, and it is off.

Do you have any character replacements defined in config_vbseo.php ?

Mert,

I have this within my config_vbseo.php:

// ****** CUSTOM CHARACTER REPLACEMENTS ******
// The following array enables you to select a replacement for characters other than the ones replaced
// by default.
$vbseo_custom_char_replacement = array();

I'm guessing I do not have any character replacements as array has no values.

Does it work correctly with vBSEO disabled and .htaccess file temporarily removed?

Yes. I disabled both and it worked. I then re-enabled htaccess and disabled the plugin and it worked, thus it must be something with the plugin somewhere.

Can you please create a support ticket with ftp , admincp and vbseo cp login information so we can investigate

Oleg replied via the ticket, suggested I add the following to te character replacement line in my config_vbseo:

$vbseo_custom_char_replacement = array('%' => '');

That did it! Thanks Oleg!

You are welcome!