I know this topic is old so I'm sorry for bumping, but this is an interesting topic that deserves some technical explanations of what went wrong.
Short answer: You can install my 
More Mission Checkpoints mod to fix Corporate Meltdown's failure triggers.
Long Answer: 
The Corporate Meltdown mission script is stored in "Gentlemen_of_the_Row_Saints_Row_2_Super_Mod_v1.9.2\optional_mod_stuff\modified\dlc05.lua".
Around line 929, the script invokes 
on_vehicle_destroyed function to set a "vehicle destroyed callback" to a truck you must protect:
	
	
	
		Code:
	
	
		function dlc05_prep_truck_initial( truck )
   -- Failure callbacks on all the trucks
   on_vehicle_destroyed( "TEXT_FAIL_TRUCK_DESTROYED", truck )
   ...
	 
 
The on_vehicle_destroyed function takes two parameters: the name of the callback function that would be called when the vehicle gets destroyed (a 
function named "TEXT_FAIL_TRUCK_DESTROYED" in this case) and the name of the vehicle (in this case, it is the truck the player must protect).
The problem is, 
there is no such function named "TEXT_FAIL_TRUCK_DESTROYED" in the mission script! When the truck is destroyed, the game calls a function named "TEXT_FAIL_TRUCK_DESTROYED", but since that function doesn't exist, nothing happens, and so the mission enters stalemate.
The intended callback function (that triggers a Game Over) exists in the mission script but is named differently and is unused:
	
	
	
		Code:
	
	
		-------------------------------------
-- Failure Conditions Handled Here --
-------------------------------------
function dlc05_fail_truck_destroyed()
   -- Kill any running vehicle chase threads
   for i, thread in pairs( Vehicle_chase_threads ) do
       thread_kill( thread )
   end
   mission_end_failure( MISSION_NAME, "TEXT_FAIL_TRUCK_DESTROYED" )
end
	 
 
The fix is change the callback name passed to on_vehicle_destroyed to the correct one:
	
	
	
		Code:
	
	
		function dlc05_prep_truck_initial( truck )
   -- Failure callbacks on all the trucks
   on_vehicle_destroyed( "dlc05_fail_truck_destroyed", truck )
   ...
	 
 
The same kind of bug exist for other failure conditions too (Helicopters and the Time Limit in Co-op mode) and similar fix is needed for them.
These bugs are fixed in my More Mission Checkpoints mod.