point helper per particle.

This might help. I re-wrote the code you originally put in but i put a test on it to only create a new point if one does not exist.

pf = $ -- select pflow source
range = #(0, 30)
ptArray = #()
ptTest = 0
 
fn fnAddKey Obj curTime =
(
	with animate on
	(
		at time curTime 
		(
			Obj.position = [5 ,obj.position.y, obj.position.z]
		)
	)
)

--call outside of loop once
MatEditor.Close()
for t = range[1] to range[2] do
(
	count = pf.NumParticles()
 
	for i = 1 to count do
	(
		pf.particleIndex = i
		ptId = pf.particleId
		if ptID > ptTest then
		(
			pPos = pf.particlePosition
			newPt = point wirecolor:yellow pos:pPos
			append ptArray newPt
			ptTest = ptId
		) else (
			curPt = ptArray[ptID]
			fnAddKey curPt t
		)
	)
)

It's kind of what I was looking for. I want to create a point helper each time a new particle is created. And at the exact time that the particle is birthed I want to animate that halper moving in the z axis "x" amount of units.

I've attached the match file to help get things started.
If you open the file and run the script I posted in the main part of this post youll see the problem.

You are having the loop which creates the particle be called 30 times causing you to make new point helpers since you have a loop running with in another loop. Also be careful with the NumParticles method since that only gives you the number of particles currently at that frame. If you know how many particles you are going to have i would just type it in. I'm also not sure what you are trying to accomplish with this code but this is what i got out of it.

pf = $		-- select pflow source
ptArray = #() 	-- Array to hold your points
range = #(0, 30)-- Fram range
ptAmount = pf.NumParticles()	--Number of particles currently on this frame

--Updated your fn
fn fnAddKey curTime ptNum pfVar ptAr=
(
disablesceneredraw()
	with animate on
	(
		for pt = 1 to ptNum do
		(
			pfVar.particleIndex = pt
			pPos = pfVar.particlePosition
			at time curTime
			ptAr[pt].position = [5 , pPos.y, pPos.z]
		)
	)
enablesceneredraw()
)--end fnAddKey fn
 
MatEditor.Close()-- No need to call this inside the Loop
max create mode

for pt = 1 to ptAmount do
(
	ptVar = point wirecolor:yellow 
	append ptArray ptVar 
)

for timeVar = range[1] to range[2] do
(
	fnAddKey timeVar ptAmount pf ptArray
)