I found the problem : AIX: The only way to run CtCmd with Perl 5.8.x is to rebuild Perl 5.8.x with the library link order changed to have -lc before -lnsl. In the Perl "Makefile" file, change the "libs" lines : ###libs = -lbind -lnsl -ldl -lld -lm -lcrypt -lc -lbsd libs = -lbind -lc -lnsl -ldl -lld -lm -lcrypt -lbsd