[plt-scheme] macro stepper fails on quasisyntax

Hi,
Risking you to think "there is that guy again" I thought you may want to know the following:
Using the Macro Stepper on the attached file produces the error shown below.
The attached program passes Check Syntax and runs well. If I remember well, earlier nightly builds did not have this problem.
Greetings, Jos Koot

DrScheme Internal Error

hash-table-get: no value found for key: quasisyntax

 === context ===
c:\program files\plt-full-369.10\collects\macro-debugger\syntax-browser\pretty-printer.ss:45:8: pp-post-hook
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:896:12
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:748:7: pr
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:896:12
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:748:7: pr
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:896:12
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:748:7: pr
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:896:12
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:748:7: pr
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:896:12
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:748:7: pr
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:896:12
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:748:7: pr
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:391:3: generic-write
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:206:18
c:\program files\plt-full-369.10\collects\macro-debugger\syntax-browser\pretty-printer.ss:41:6: pretty-print-syntax method in 
syntax-pp%
...

Standard Output

hash-table-get: no value found for key: quasisyntax

 === context ===
c:\program files\plt-full-369.10\collects\macro-debugger\syntax-browser\pretty-printer.ss:45:8: pp-post-hook
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:896:12
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:748:7: pr
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:896:12
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:748:7: pr
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:896:12
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:748:7: pr
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:896:12
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:748:7: pr
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:896:12
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:748:7: pr
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:896:12
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:748:7: pr
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:391:3: generic-write
C:\Program Files\PLT-FULL-369.10\collects\mzlib\pretty.ss:206:18
c:\program files\plt-full-369.10\collects\macro-debugger\syntax-browser\pretty-printer.ss:41:6: pretty-print-syntax method in 
syntax-pp%
...

exception raised by error display handler: hash-table-get: no value found for key: quasisyntax; original exception raised: 
hash-table-get: no value found for key: quasisyntax


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.racket-lang.org/users/archive/attachments/20070420/6b0f0ffc/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: records.ss
Type: application/octet-stream
Size: 6088 bytes
Desc: not available
URL: <http://lists.racket-lang.org/users/archive/attachments/20070420/6b0f0ffc/attachment.obj>