[plt-scheme] read error

setup-plt is barfing when it encounters a source file that uses a  
custom reader. I have a subdirectory "collects" with a file "js.js"  
that has a custom #reader line at the top. With the Nov. 3rd build,  
setup-plt seems just to skip this file completely. But with the Nov.  
8th build (which I *believe* predates Robby's changes to zo behavior),  
it insists on compiling the file, even if I create an info.ss that  
includes it in the compile-omit-paths list. And then I get this error:

setup-plt:   collects/compiled/js_js.zo::1396: read (compiled): ill- 
formed code [../../../mzscheme/gc2/../src/read.c:4648]

How can I debug this error?

Thanks,
Dave