Use packages "differ" and "distrib" in 5.10.0-release candidate 3?

Dear all,

I have a problem using the packages "differ" and "distrib" in the newly
released version of Maxima. I downloaded "maxima-5.9.3.99rc3.exe" for
Windows XP system, and tried my previous uses in it for consistency
purpose. But I couldn't use the packages "differ" and "distrib" as
before(I could use them in 5.9.3). 

As I know, "differ" is a package used for solve difference equations.
But I can't find this package in this version:

(%i13) batch(differ);
Could not find `differ' using paths in file_search_maxima (combined
values: 

Also, in "distrib" package, rnormal (m,s,n) ought return a normal
random variate N(m,s), with s>0. Calling rnormal with a third argument
n, a random sample of size n will be simulated. 

But after I load the package "distrib", I can't use this command
properly anymore:

(%i14) load(distrib);
load("numericalio.lisp");
rnormal(0,1,40);

(%o14)
C:/PROGRA~1/MAXIMA~2.99R/share/maxima/5.9.3.99rc3/share/contrib/distrib/distrib.mac(%i15)

(%o15)
C:/PROGRA~1/MAXIMA~2.99R/share/maxima/5.9.3.99rc3/share/contrib/numericalio/numericalio.lisp(%i16)

(%o16) rnormal(0,1,40)


Do you know why this is happening? Thank you very much for your time
and I am looking forward to your reply.


Jinhu Li