[plt-scheme] Problems with DrScheme3m

I downloaded the "Full" version of PLT Scheme 301.13 (for Windows XP) to
test the 3m versions of DrScheme, etc and see what effect they have on the
simulation collection.  The examples work fine under DrScheme, but fail with
the following error under DrScheme3m

ffi-lib: couldn't open "C:\\Program
Files\\PLT-FULL-301.13\\collects/plot/compiled\\native\\win32\\i386\\3m\\lib
plplot.dll" (The specified module could not be found.; errno=126)

The problem seems to be that there is no "3m" subdirectory at the
appropriate place in the compiled plot collection.

I assume there is some difference between the 3m version and the non-3m
version since just copying the existing ones into a subdirectory doesn't
work.

Is there something else I need to do or is this an error?

Doug