And what output would you want in those cases? The text '(none)' where the date should be?

#! perl -slw
use strict;

while( <DATA> ) {
    $_ .= <DATA>;
    print join',', m[
        Username: \s+ (\S+) \s+ Owner: \s+ ([^\n]+ ) \n
        Last\sLogin: \s+ ( .+ ) \s \( [^,]+, \s+ (.+) \s\(
    ]x;
}

__DATA__
Username: JANDERSON                            Owner:  JOE ANDERSON
Last Login: 14-JAN-2002 08:14 (interactive),  4-MAR-2002 17:09 (non-in
+teractive)
Username: PBARRETT                           Owner:  PAUL BARRETT
Last Login: 18-JAN-2006 08:14 (interactive),  24-MAR-2005 17:09 (non-i
+nteractive)
Username: LARRY                            Owner:  LARRY FINE
Last Login:            (none) (interactive),            (none) (non-in
+teractive)
Username: MOE                            Owner:  HARRY MOSES HOWARD
Last Login: 11-JUL-2002 18:08 (interactive),            (none) (non-in
+teractive)
Username: CURLY                            Owner:  JEROME HOWARD
Last Login:            (none) (interactive), 12-SEP-1997 11:33 (non-in
+teractive)
[download]

Gives

P:\test>junk
JANDERSON,JOE ANDERSON,14-JAN-2002 08:14,4-MAR-2002 17:09
PBARRETT,PAUL BARRETT,18-JAN-2006 08:14,24-MAR-2005 17:09
LARRY,LARRY FINE,(none),(none)
MOE,HARRY MOSES HOWARD,11-JUL-2002 18:08,(none)
CURLY,JEROME HOWARD,(none),12-SEP-1997 11:33
[download]