Singh was writing a mission for the FRED Academy which recently corrupted itself on saving (It took out his .bak too so it obviously saved incorrectly at least twice). 
Seeing as how he's a fellow MG team member as well as going through the Academy I went the extra mile and checked it against an earlier version of the mission to see if I could spot what caused the error. 
On looking through the mission I found that the debriefing stage on one mission looked like this (I've trimmed out the actual debriefing text). 
#Debriefing_info
$Num stages: 2
$Formula: ( is-goal-true-delay 
   "protect fleet" 
   0 
)
$Multi text
    XSTR("Some Text Was Here.", -1) $end_multi_text
$Voice: none.wav
$Recommendation text:
    XSTR("", -1)
$end_multi_text
$Formula: ( is-goal-false-delay 
   "protect fleet" 
   0 
)
$Multi text 
When I change that code to the following the mission started working again. 
#Debriefing_info
$Num stages: 2
$Formula: ( is-goal-true-delay 
   "protect fleet" 
   0 
)
$Multi text
    XSTR("Some Text Was Here.", -1)
 $end_multi_text
$Voice: none.wav
$Recommendation text:
    XSTR("", -1)
$end_multi_text
$Formula: ( is-goal-false-delay 
   "protect fleet" 
   0 
)
$Multi text 
Are the line breaks before the $end_multi_text really that important? If so would it be possible to find out why FRED didn't include them when it corrupted the mission? 
Hmmm. I suppose I should ask Singh which version of FRED he's using. I don't think it was the most modern one.