LOAD problem



Hallo
I am experiencing a strange problem which I am not able to understand:
Like I said in my previous messages, I am trying to export MAXIMA
expressions to FORTRAN.
So, I loaded the following two lisp files:
LOAD("C:/Programme/Maxima-5.9.1/share/maxima/5.9.1/src/commac.lisp")$
LOAD("C:/Programme/Maxima-5.9.1/share/maxima/5.9.1/share/contrib/90.lisp")
I get the following message:

 Warning:
FUNCTIONP is being redefined.
Warning:
BREAK is being redefined.
Warning:
GCD is being redefined.

After this, my code exits with the message
"stdin:1500:Incorrect syntax: then is not an infix operator
 := IF (i = j) THEN.  "

Although the code is error free. However, when I do not loade commac.lisp,
my code runs but I cannot convert expressions to F90 format. On the other
hand, if i load the "commac.lisp" at the end of my file, all the variables
are lost !
Any idea where I am wrong?
Vijayendra