Need help making a height map

[trashgarbage666]

I've tried following a handful of tutorials, and in all of them, there's a point where they ask you to use a program called TESAnnwyn. The idea is, you feed the program your height map and it spits out an .ESP that can be loaded into the GECK. Unfortunately, all the .ESPs I've generated freeze the GECK when I try loading them. Would someone with some experience with TESAnnwyn be willing to take a look at my height map and the commands I'm giving it to see where I'm going wrong?

 

Here's the image I'm working with, in .PNG and .RAW format.

https://drive.google.com/file/d/1w5nLnjm5YVa9a29pNKKm57Je3LXcqWsF/view?usp=sharing

 

Here are the commands I'm giving TESAnnwyn. I save this as a .BAT in my TESA folder and run it there.

TESAnnwyn.exe -i FalloutNV -p 1 -b 16 -d 4096x4096 -x -64 -y -64 -h 10000 -s 3.0 -w "VBNVWorldGrandCanyon" heightmapimage.raw

 

EDIT: I noticed the .ESP TESAnnwyn gave me didn't have a master, which may be the reason why it causes the GECK to freeze. However, trying to add FalloutNV.ESM to its masters in FNVEdit gave me this error:

 

[00:00] Error saving tesannwyn.esp.save.2021_04_19_21_54_22: Assertion failure (P:\TES5Edit\wbImplementation.pas, line 14743)

​[00:00] Errors have occured. At least one file was not saved.

No idea what it means! Perhaps someone here knows?