Trying to understand Security Token errors more

[RedGTiVR6]

I'm trying to understand the reason a security token error would be thrown...only sometimes.

I understand that if it's thrown all of the time, it's because a few lines of code are missing (specifically if it's in regards to a plug-in).

However, what does it mean if I'm getting these notifications about security tokens occasionally?

For example:

Script Call Backtrace

=====================

#0 E:\Inetpub\vbforum\includes\functions.php line 2688: eval()

#1 E:\Inetpub\vbforum\global.php line 379: fetch_error(security_token_missing,sendmessage.php)

#2 E:\Inetpub\vbforum\downloads.php line 137: require_once(E:\Inetpub\vbforum\global.php)

#3 E:\Inetpub\vbforum\vbseo.php line 1470: require(E:\Inetpub\vbforum\downloads.php)

 

POST Variables

==============

Array

(

    [securitytoken] =>

    [ajax] => 0

)

 

Request URI

===========

/downloads.php?do=add&id=



Referrer

========

http://xxx.xxx.xxx/downloads.php?do=add&cat=

How can I trace back what would be throwing these?

Is it just a glitch?

Is it just something that happens? Should I just ignore them?

I'm using a mod that notifies me of these Security token errors because I was trying to track down which mods hadn't been updated for the vBulletin update back when vBulletin made the change.

I'm just trying to better understand.

Thanks for any information!