StepTalk and object construction.

(Note I am using:
 	cvs -q -d \
	":ext:[email protected]:/cvsroot/gnustep"\
	update -dP -D 20041203 gnustep/dev-libs/StepTalk)

I tried the following example code from ESUG2003 slides:
| object method source engine |
   object := STScriptObject scriptObject.
   engine := STEngine engineForLanguageWithName:'Smalltalk'.

   source := 'sayHi Transcript show: \'Hi.\'. ^self'.
   method := engine methodFromSource:source
                    forReceiver:object
                    inEnvironment:Environment.

   object addMethod:method.
   object sayHi.

with stexec and I receive the error:
"stexec: Uncaught exception STInterpreterGenericException, 
reason: No execution environment set"

I can get the method to execute 'manually' by using 
"executeMethod:forReceiver:withArguments:inEnvironment:".
Why can't I get it to work as written?

Thanks,

Matt