@Kernelpanic They say a picture is worth a thousand words. So, I cooked up a fresh InForm-PE setup in a fresh environment from scratch. This explains, how I would setup everything step by step. Hope this will help.
Download the latest QB64-PE and InForm-PE and save those in a directory (in this case C:\Lab).
Extract both archives.
Notice the directory structure on the left. This is important.
Enable "Output EXE to Source Folder". Notice the dot. This is off by default (which is pure evil IMO).
Run "setup_inform_win.cmd" to compile InForm-PE.
Wait for everything to compile.
Done.
Then I create C:\Lab\Projects\Four Up.
Create the form using UiEditor and save it in C:\Lab\Projects\Four Up.
Note that we cannot compile it yet, because the InForm dependencies are missing.
To resolve the dependency issue, copy the InForm directory in the InForm-PE directory, and...
...paste it in our project directory (Four Up).
In the end we should have something like this. The following screenshots show compiling and running the project.
Note that I am working on solution in a future update of the InForm UiEditor where it will automatically copy all required dependencies to the project directory.