[plt-scheme] teachpacks breaking in 4.2

At Mon, 8 Jun 2009 14:41:12 -0400, Stephen Bloch wrote:
> I'm trying to install my tiles and sb-world teachpacks into 4.2.   
> Both of them worked (alone or together) in 4.1.3, but when I add  
> either or both of these teachpacks and hit "Run", I get a horrible  
> error message:
> 
> require: namespace mismatch; reference (phase 0) to a module "C: 
> \Program Files\PLT\collects\scheme\private\kw.ss" that is not  
> available (phase level 0)
> 
> First, what's going on?
> Second, how do I fix the teachpacks so they work with 4.2?  (And,  
> preferably, with 4.1.x as well.)

I can answer the second question, at least.

The "tiles.ss" teachpack file uses the `mzscheme' language. Changing it
to `scheme/base' solves the problem for me:

 (module tiles scheme/base
 (require (planet "tiles.ss" ("sbloch" "tiles.plt" 1 12)))
 (provide (all-from-out (planet "tiles.ss" ("sbloch" "tiles.plt" 1 12))))
 )

Meanwhile, we'll figure out why using `mzscheme' fails.