Referring to the files inside a hook file

I have hook files that represent projects. Each contains just one hook, linked to the main project folder on my machine.
to archive this folder, I need to access it through AppleScript.

project name is PROJ1
I have a hook file named PROJ1.hook which contains a hook of the form:
If I copy past this URI in Safari, it opens a folder called PROJ1somewhere on my hard drive.

So far, so good.
I need to get the path of the folder in AppleScript, in order to move it to my archive repository.
This is what I have (argv contains the path to the hook file itself - i’m passing it from Alfred)

set theHookFile to POSIX file ((item 1 of argv) as string)
tell application "System Events"
	set theHook to read theHookFile
end tell
tell application "Hook"
	-- get the folder that's referenced by the hook
	set theBookmark to the bookmark whose address is theHook
	set theHookPath to the posixPath of theBookmark
end tell

which fails telling me:

Can’t get bookmark whose id of it = "hook://file/blabla?p= blabla&n=PROJ1".

Which is weird, because I thought I’d just confirmed that there is indeed a bookmark with that address … I’m probably doing something illegal in AppleScript, but I havent been able to figure out what…

thanks for any help!

Should it be get bookmark id theHook as in the example here:

Hi thanks, but no, bookmark id theHook gives me the same error