Eh?
I think you're taking things a bit too far...
Are you saying you're missing the extensions, or can't support them? Because that's not possible.
The only problem that I can think of that comes close to matching your's is when Dooey was accidentally using an older version of Cave Editor; are you using version 0.95?
And, just to double-check things, you're not opening the EXE in an empty folder, are you?
If, for say, the Data folder isn't in the same folder as the EXE, Cave Editor wouldn't have any images to load....
Then again, you said Sue's loaded them, right? So the folder's probably in the right place....
And you're using a clean EXE? One that Sue's Workshop hasn't touched, yet?
I don't think that's the problem, but it doesn't hurt to be safe....
And randomly delving into the source code will not help things, since we have no idea what the problem even is.
Now that I think of it, mayhaps it's your computer or something on it that's messing with Cave Editor? No one else seems to have ever had this problem, before...
Not that I have any idea on how to test this thought....
Hmm, got any more details? The files your using, perhaps?