thing plant
and
thing plant0

if((IsMulti()) && (!IsServer())) Return;
else SetPulse(0.1);
SetPulse(0.1);

for(i = 0; i <= 39; i = i + 1)
{
	if(Plant < 0) Return;
	plantLVec = VectorSub(GetThingPos(NearestPlayer), GetThingPos(Plant));
	plantLVec = VectorSet(VectorX(plantLVec), VectorY(plantLVec), VectorZ(GetThingLVec(Plant)));
	SetThingLook(Plant, plantLVec);
	Return;
}

        
Code:
        
if((IsMulti()) && (done))
{
	done = 0;
	numplayers = GetNumPlayers();
	HeapNew(0, numplayers);
	PrintInt(numplayers);
	for(j = 0; j < numplayers; j = j + 1)
	{
		for(i = 0; i <= 39; i = i + 1)
		{
			if(Plant < 0) Return;
			// now store the distance of each player.
			HeapSet(j, VectorDist(GetThingPos(Plant), GetThingPos(GetPlayerThing(j))));
			// find the smallest heap at this point
			if(distance == -1) distance = HeapGet(j);	// player 0's distance from plant.
			if(distance < HeapGet(j))
			{
				distance = HeapGet(j);	// heaps rock!
				NearestPlayer = GetPlayerThing(j);
				plantLVec = VectorSub(GetThingPos(NearestPlayer), GetThingPos(Plant));
				plantLVec = VectorSet(VectorX(plantLVec), VectorY(plantLVec), VectorZ(GetThingLVec(Plant)));
				SetThingLook(Plant, plantLVec);
			}
		}
	}
	HeapFree();	// free the heap for the next pulse.
	distance = -1;
	done = 1;
	Return;
}


    

That's just a mess. What's done in there for? To stop pulse from running twice at the same time? Not going to happen even with the two SetPulses. And there's a useless return at the end.

And now the main logic. These loops are going through every player and then through every plant to find the closest player. It's backwards. You should be looping through the plants first, then finding the closest player and making the plant look at it.

There's no reason to use the heap at all. The way you have the distance checking set up looks wierd - each plant is checking the distance of the last plant to see if it's less than its own distance from the player...

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Author of the JK DataMaster, Parsec, Scribe, and the EditPlus Cog Files.