[plt-scheme] Collection not found error - porting old scripts

Hi guys
I have some problems loading scheme scripts - I have a simple script
which requires another script which has this code at the top of it:

(module base mzscheme

(require (prefix vge: "base-low.ss")
	 (lib "kw.ss"))

It doesn't work.
When I change mzscheme to scheme, it doesn't work either.
But when I change it to scheme/base, I get an error in the require
'tag'..
This is probably pre-PLT 4 scripts, so any help is appreciated
regarding how to port this.

I wasn't able to learn anything useful from browsing the manuals.

The 'base-low.ss is actually an extension.

Do I need to change my scripts?
Or my extension?
Or both?