The original macro that uses a Finder selection does work with paths that include spaces. Those are full paths (/User/etc. not ~/Documents).
The question I have is whether your Path variable is a full path. The error message says it is not.
I'd investigate that.
I am revisiting some old discussions....
First RIP JMIchaelTx
Second, after several incomprehensible discussions, but learned solutions, above, I stand by my original comment (number 4) to use ...
a better finder rename
this saves so much Regex pain and anguish as it shows you exactly what is going to happen
It also has a lot good stuff if you are into Exif files for photography.