Sorry for you Master Zip Zero, and i'm agree with what said SLuckyD. I can just confirm that the 0.23beta version of TESAnnwyn and the Skyrim CK are working well for what you try, i did it with your RAW, ESP and no problems at all.

I just tried the one thing I hadn't done yet. I converted the file into a .esm. It totally works! Even though the world is named 8192, and the landscape is horribly rough, at least I can load it now!
So, I guess I'll remake it, and turn it into an ESM. Are there any drawbacks to this? Should I make sure the heightmap is smoothed out first, or should I place something in it, or something?

U do not need an esm to make it work ...

Prometheus is right...and how did you convert it? By renamming .ESP to .ESM? Even if you do this, you need to save it again to put a "ESM flag" in your saved file, so there is no reason you could do this if you can't open file, whatever is extension, in CK...

But did you try to open only the ESP file, without the Skyrim.esm? If it works, verify the integrity of your Skyrim.esm file, your RAM available, etc. You can see what the CK is doing when freezing at 96% by using softs like Sysintenals Process Monitor (btw, have a look at Sysinternals Tools, very very useful set of tools).

I used Tes4Gecko to convert it. As an esp, it didn't work, as an esm, it did. I'm pretty sure that means that I need it as an esm for it to work.

Mine was an ESP, but my worldSpace was so big that I DO convert to ESM for other reasons. But something I did when still messing wth Oblivion was to do a huge map in sections... instead of my entire 9 quads (which would be a 6144x RAW, 4096x is only 2x2 quads... ), try it in single-cell chunks... ensuring to use the correct coordinate offsets, then merge the resulting ESPs into one and delete/Snip any cells you don't need. But if a relatively small 4 quad ESP isn't working... I dunno. You can also do a 6144x4096 or whatever combo.. it doesn't have to be a perfectly square heightmap; just be sure the resolution corresponds to your projected number of cells/quads.

On a different note, you can change the 8192 name in the CK. It sounds like you may have accidentally left out a letter on one of the switches for that particular attempt. I got fed up with having to type it all out; so I placed my working command-lines in one of my "notes" text files and just copy/paste it over... changing names/etc as appropriate. That way I never mistakenly type the switches, I don't have to remember anything, etc. I did quite a bit of testing with Annwyn for Obliv; but as we all know - Skyrim's another beast altogether.

Not for nothin, but I'd avoid using 3rd party tools as much as possible for messing with Skyrim stuff (not Annwyn, but Gecko/etc). I hadn't heard of Gecko working for Skyrim (that was my go-to app for Obliv..), but I guess a simple ESP-ESM convert wouldn't be too bad. I still think it's strange that it works though... Gecko was Obliv while Skyrim is basically Fallout (when it comes to ESP/ESM structure and game data); or at least closer to the latter than the former.

[EDIT: regarding leaving your heightmap 'bumpy'... I would do ALL work with the heightmap in Photoshop/image editor. I did this in Oblivion and it was WAY easier than trying to coax the bloody map editor to what I wanted. Need it flatter or higher? Just darken/lighten the whole image. Want small bumps for realistic land? Do a noise filter or something like that. The main point is that Skyrim's heightmap editor is KNOWN not to work... they even say so in the wiki I believe. Much of its functionality was disabled or broken... making Photoshop pretty much essential for decent landscaping.

Your bumpiness may just be the format or settings you used to create your RAW. I remember that being kinda tricky; I think I just used the doc that came with Annwyn... but find directions that work and stick to em. Trying to load a RAW back into Photoshop was always nightmarish as well, so try not to use that as an indicator unless you know how to get it working correctly.]