The version of splot in the SIPB locker is quite a bit out-of-date.
The newest version is available in /pub/splot on masala.lcs.mit.edu.
Someone should:

a) get the new version;
b) check which of the fixes in our version need to be merged into the
   new version, and merge them;
c) submit the fixes that needed to be merged back to the maintainer of
   the program; and
d) install the new version in the sipb locker for all platforms.

  jik