building on 1.8.1 on windows / build-wxmsw.bat problem

I ran into a problem building pgAdmin on Windows: I followed the
instructions at

http://svn.pgadmin.org/cgi-bin/viewcvs.cgi/branches/REL-1_8_0_PATCHES/pgadmin3/INSTALL?view=markup

but the script in step 4 craps out. Specifically, the loop of running
vcbuild /convert on all the dsp project files errors out (on each file),
saying

"Unable to convert project.
Please make sure this is a vaild Visual C++ 4.0 or later project."

Checking the .dsp files, their headers say

# Microsoft Developer Studio Generated Build File, Format Version 6.00

I got the wxMSW source package for wxWidgets 2.8.7.

Any ideas?

Thanks,
--
Maciek Sakrejda
Truviso, Inc.
http://www.truviso.com