Your AHK script probably doesn't work in Opus -- in fact, literally only works in Explorer, I would bet -- because of this line at the top of it:
#ifWinActive ahk_class CabinetWClass
CabinetWClass is the window class Explorer uses. The first line of your script is saying it should not do anything unless Explorer is the active window. The rest of the script also does things that will only work with Explorer, since it's assuming certain controls exist in the window and reading things directly out of them. (That might not even work with future versions of Explorer, let alone Opus.)
We aren't very familiar with AHK, and focused on the claim that hotkeys weren't working in Opus, so this isn't something we noticed at first. Also why, if you're having trouble with an AHK script, it's better to ask on the AHK forums than on here.
If you want to set something similar up using Opus, there are a bunch of ways you can do it, including scripts that generate custom dialogs or pop-up menus and are triggered by hotkeys...
But the easiest is probably to just have a simple menu on your normal toolbars, with each of the filenames you might want to create.
How to Create New/Empty Files gives the commands to create new, empty files with the names you want.
Editing the toolbar should get you up to speed on creating menus and buttons, if you aren't already familiar with that part of Opus.
When making menus and buttons, you can make them keyboard controllable by placing a & character before another character in their labels.
For example, if you name your menu Cre&ate Empty Files then you can open the menu from the keyboard by pushing Alt+A. If you name one of the items within it that creates a file &Create file 1, you could push C after opening the menu to quickly access it. (Or just use the cursor keys after opening the menu.) Of course, it can be driven via the mouse as well.
You can also give hotkeys to individual menu items, so you could for example push a hotkey to instantly create a certain file in the current folder without anything popping up.