Cannot reproduce, which is unfortunate. Error is with your eu4 installation. I suggest uninstalling eu4, then deleting the leftovers (which are probably the issue here) from steam install folder, and then reinstalling.
From the log it appears as if you entered either a blank space for the output name or a character that could not be converted to ascii. Check that "output name" field and be sure it's empty. Delete whitespace characters if you see them.
My mistake. You appear to have ran the converter itself and not the frontend which is needed to setup the conversion. Be sure you have unpacked the entire zip file while maintaining directory structure into a new folder, that you don't have buggy antivirus programs like Avast or AVG enabled while running the converter (or just whitelist the converter in them) and run the ConverterFrontend.exe and not CK2ToEU4Converter.exe.
Sorry again but that is precisely what I have already done. I unpacked the zip and ran ConverterFrontend.exe, and that produced the error message I referred to in my first post. I'm not at my PC at the moment but all it did was show a dialog box containing the error message "Unhandled unknown exception, terminating the application". I also happened to run CK2ToEU4Converter.exe but that made a dos box pop up for a moment and did nothing. As far as I understand it I am following the installation instructions to the letter.
ConverterFrontend.exe generally doesn't crash unless it misses its dll files which should be in the zip file with it. It is known to happen that antivirus programs can just delete stuff from the zip file while it's being downloaded, please disable them. Also, it wouldn't hurt to run VC_redist.x64.exe inside the converter's folder. After you've done all that and if it still does not work, please upload the screenshot of the error and the folder where you unpacked the converter.
I gave it another try and still not successful. Clicking on ConverterFrontend.exe generates the same message as before. I have attached it, as well as log.txt which looks the same as before. I have also counted that all files in the zip extracted successfully. I'm only using Windows native antivirus, nothing else.
"and the folder where you unpacked the converter." The log file you are uploading is an internal log created by the converter, not the frontend. Frontend has its own log, also named log.txt in the directory above. If you unpacked everything into the same directory, it won't work. I need to see the screenshot.
Shattering is inherently imprecise. You can be HREmperor ruling out of a barony, and then wouldn't get concerted as baronies are integrated. If it really bothers you I can take a peek at what's going on, but generally speaking, ruling multiple empires (HRE and one other) is known to mess things up, as well as potentially having kingdoms and so on. It all depends.
Okay I have now attached two pictures to show how I unzipped the files. I created a folder on my desktop called "CK2toEU4 Converter" and unzipped the files into there. One folder beneath is the folder "CK2toEU4" which is the highest folder in the zip. I have also included the log.txt file one folder above the one I attached before. Since it has only two lines and they don't appear to be logged errors, I thought it was unimportant before but here it is.
Yeah, so, all looks well from over here. Filesizes look right, all files in place. If it crashes then the issue is either with the computer memory/windows/windows defender or something else. I'm out of ideas. Why not download any other converter and see if they work? If they all crash then issue is definitely on your end.
Your paths should look something like this:
