This works for the sample supplied.

#! perl -slw
use strict;

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