What kind of parameter does that script expect ?
As it is, you're passing it a string. If it's supposed to be the dataset in the referenced tag, you'll need to use {value}{source} instead of a string.
Another thing to consider: Tags do not depend on a project. So that script needs to be in the gateway scripting project, or it just won't work. Do you have any error in the logs ?
One last thing: I try to avoid scripts in tag evaluation as much as possible. There are countless discussions about this on the forum, but what I (personally) dislike the most about it is how difficult maintenance gets when you have scripts all over the place. I'd probably use a memory tag and a gateway event. Or Phil's integration toolkit to unlock many new expression functions, which might allow you to get rid of the script entirely.
What does your script do exactly ?