The following 'script' works for me in 'Ikarus Scheme':
#!/usr/bin/env scheme-script
(import (rnrs))
(display (command-line))
(newline)
ebg@ebg$ ./ik.scm a b c
(./ik.scm a b c)
ebg@ebg$ ikarus --r6rs-script ./ik.scm a b c
(./ik.scm a b c)
and for Petite
ebg@ebg$ petite --script ~/ik.scm a b c
(/Users/ebg/ik.scm a b c)
Note that officially (import (rnrs programs (6)))
won't import display
so as written your code should fail.