Changing Error Message not in Fmbadhandler

[MeganXsalta]

I've had a devil of a time getting past the old "Image verification string missing...." message, until I discovered that if a person visits the site for the first time, and has their cookies set to NOT accept cookies from 3rd parties, only then do they run into that error. It was extremely frustrating, as I couldn't seem to replicate that error on my end, since I have the cookies accepted from the sites my forms are on.

Anyway, here's my problem: On that particular error message, when it tells people "Image verification string missing. This is probably a fault on the server.", I want to add a note that it's because their cookies for our system are disabled, and I've still received their message and will get back to them, yada yada. I've tried searching for that error in the fmbadhandler script, but can't seem to find it. Am I simply not seeing it, or is that an error I can't change?

[MeganXsalta]

In case anyone else was having trouble with error messages that aren't found in fmbadhandler, I found a large section of error messages in formmail.php starting around line 900. I found this specific error on line 1867. It's outside the safe configuration lines though, so change with caution.

I'm not sure how I managed to miss them before.