[plt-scheme] Odd require/provide compile error

Hi all,

I'm getting a weird error that I'm not sure how to debug. When  
compiling an application on a Debian box, mzc raises the following  
exception:

syntax-local-module-required-identifiers: not currently transforming  
module provides

  === context ===
/usr/local/plt-4.2.1.5/collects/scheme/private/reqprov.ss:687:27
/usr/local/plt-4.2.1.5/collects/scheme/private/reqprov.ss:677:12
/usr/local/plt-4.2.1.5/collects/scheme/private/reqprov.ss:671:5
/usr/local/plt-4.2.1.5/collects/scheme/provide-transform.ss:51:2:  
expand-export
/usr/local/plt-4.2.1.5/collects/scheme/private/reqprov.ss:604:17:  
transform-simple
/usr/local/plt-4.2.1.5/collects/scheme/private/reqprov.ss:600:2
/usr/local/plt-4.2.1.5/collects/compiler/cm.ss:120:0: compile-zo*
/usr/local/plt-4.2.1.5/collects/compiler/cm.ss:206:0: compile-zo
/usr/local/plt-4.2.1.5/collects/compiler/cm.ss:246:2: do-check
/usr/local/plt-4.2.1.5/collects/compiler/cm.ss:293:4
for-loop

This doesn't seem to occur on my (OS X) laptop. Furthermore, by  
messing with the compile order (by specifically choosing modules from  
my program to compile), I seem to be able to get around the problem  
and compile the app.

I'm using PLT 4.2.1.5 on both machines.

I am doing some shenanigans defining shortcut require/provide forms  
using a macro from Unlib called define-library-aliases. I guess that  
could be the culprit. The main function in the implementation is make- 
planet-library-transformers, defined here:

http://svn.untyped.com/unlib/trunk/src/require-internal.ss

Any advice appreciated!

Many thanks,

-- Dave