Installing new GTK version did not solve it, but he told me to copy the GTK2 Runtimes dll files to the emu folder so it runs at all. Now It seems to work perfectly.

Well, you'd better not do that if you want multiple GTK+-using applications to unconditionally run simultaneously

Programs embedding their own copies of the GTK+ DLLs, irrespective of Windows' harmful limitation wrt. DLL caching (the DLL cache being by basename only, rather than by full path), e.g. Wireshark, are precisely part of the problem; GFM/TILP/TIEmu rightfully don't do that.
The other part of the problem is the existence of multiple incompatible GTK+ runtimes for Windows. The one used by GFM/TILP/TIEmu has been unmaintained for two years, which means that we'll have to switch to another one, presumably the one used by The GIMP.

Well, if you don't use any other GTK+-using application and the emulator simultaneously, you can leave things in their current state
Just be fully aware that multiple versions of the GTK+ (or whatever else) DLLs running simultaneously, can also create "missing function in DLL" errors.

Ah ok thanks for the info. So this means that if I ever do that, then I will never be able to use Levak emulator again on this computer (since not including the DLLs in the folder causes errors)

You can paste your dlls to system32

Is it much safer than what Lionel told me to not do, though?

It is just in case, if you want to run 2 programs using this at the same time.
It probably will work, however you may not remember all those dll names,
and so you will keep them "forever" in your system.

But most likely you won't need to run two programs at the same time, you can be fine with things as they are now

Necropost.
I don't know if there is much point in using xspire's nspire_emu with gtk (not Levak's, he made the batch files), due to the fact that the screen becomes grainy, and also that it is v026 and hasn't been updated much.
EDIT: Re tried it again after downloading new version of GTK runtime and it is grainy because I resized the window (it doesn't quite fit on a 1280x800 screen) and it is not grainy. However it only works for v026 and can't run OS 3.0

CX feature filled emulators?
Oh I'm using Windows, so no need for Wine, but not sure what you're getting at with CX feature filled emulators.
goplat's requires boot1 to emulate CXes tho.

Yeah I know. But it's a problem if I don't own a CX. Unfortunately

Oh well. I liked xspire's nspire_emu_gtk. Sad to say it's outdated now and there haven't been any new posts from xspire from unitedTI.