[plt-scheme] scheme/sandbox and gui stuff?

I'm seeing the following error when I try running this program under 
DrScheme's module language:

#####################################
#lang scheme/gui
(require scheme/sandbox)
(define e (make-evaluator 'slideshow))
#####################################



The error is:

###################################################################
Welcome to DrScheme, version 3.99.0.25-svn16may2008 [3m].
Language: Module; memory limit: 512 megabytes.
ACK! didn't find drscheme's stackframe when filtering
. . exception raised by error display handler: directory-exists?: file 
access denied (/ exists); original exception raised: dynamic-require: 
unknown module: '#%mred-kernel
###################################################################


I haven't been able to use the gui module in an sandbox evaluator yet. 
Any help would be appreciated.  Thanks!