You are perfectly right, this feature is unfinished. Let us hope it will be fixed quickly.
Did you try in slow mode ? You have the option in the options tab. This mode is more secure. Maybe you can post your file here, if it is not confidential, and we will be able to test.
The problem comes surely from the library we are using. There is no intention to convert anything, but parsing a Pdf to merge two page is no fun. Fortunately, Tomas Resquin restarted the maintenance of PdfBooklet and I hope he will be able to upgrade this library whhich may solve the problem you mention.
I have never seen that. One possible reason is that there are permissions problems. PdfBooklet does not follow the standards because all files are in the same directory. If you install it in ProgramFiles, Windows may not allow all permissions. The simple solution is generally to install in a non system directory, like C:\utils Can you try it and see if it solves your problem ?
Where did you find an image ? I am struggling to find one but raspbx.org is not accessible, and the links to download on raspberry-asterisk.org seem to be all dead. more precisely, it is the subdomain download.raspberry-asterisk.org which is not accessible. If I can find an image, I may perhaps help you, since I am familiar with Raspbx.
I read somewhere that Raspbx is not compatible with Pi4 8G.
Where did you find an image ? I am struggling to find one but raspbx.org is not accessible, and the links to download on raspberry-asterisk.org seem to be all dead. If I can find an image, I may perhaps help you, since I am familiar with Raspbx.
Note that on my system (Windows 8.1) the error does not exist. On which system are you running ?