[plt-scheme] stdc++ linking problem

I am having the following linking problem when running MrEd.  I have two (what 
I thought to be) identical systems running SunOS 5.8.  MrEd is built with 
--enable-shared.  LD_LIBRARY_PATH is set the same on both and both use the 
same version of Gnu ld.  On one, MrEd runs fine.  On the other I get:

ld.so.1: mred: fatal: libstdc++.so.5: open failed: No such file or directory
Killed

ls /usr/local/lib/libstdc++.* for both systems returns:

/usr/local/lib/libstdc++.a          /usr/local/lib/libstdc++.so.3@
/usr/local/lib/libstdc++.la*        /usr/local/lib/libstdc++.so.3.0.0*
/usr/local/lib/libstdc++.so@

So I don't see how libstdc++.so.5 can be found on one machine and not the 
other (I would expect both machines to fail to start MrEd).

Any ideas?

Is there some way to do a "which libstdc++" on the system that is working?

Thanks.  (I realize this probably has nothing to do with PLT Scheme, but I 
don't know where else to ask.  Sorry.)

-d