Closing input string port causes error

[ds26@goldshoe.gte.com (Dorai Sitaram)]

When going from Scsh 0.6.1 to 0.6.2 I found a
program of mine stop working with the error 

  Error: returning zero values when one is expected
  (values).

Turns out this is caused by close-input-port on 
a string input port (created with
make-string-input-port).

On a larger note, is it acceptable in Scsh to not
close string ports?  I remember some (non-Scsh) Scheme
manuals saying string ports didn't need closing.