[ABE.pm] arg isn't numeric?

[Phil Lawrence]

Anyone see why I'm getting this error?  (source at bottom)  Shouldn't 
the strings auto-convert to numeric?

 > date_algo.pl '2000-05-07', '2003-11-26', 10
Argument "07," isn't numeric in subroutine entry at ./date_algo.pl line 
13 (#1)
     (W numeric) The indicated string was fed as an argument to an operator
     that expected a numeric value instead.  If you're fortunate the message
     will identify which operator was so unfortunate.

Argument "26," isn't numeric in subroutine entry at ./date_algo.pl line 
13 (#1)
begin:  2000-05-07,
end:    2003-11-26,
per:    10
delta:  1298
intrvl: 130


SOURCE:
#!/usr/local/bin/perl
use warnings;
use diagnostics;
use strict;

use POSIX;
use Date::Calc qw( :all );

my $begin = shift();
my $end   = shift();
my $per   = shift();

my $delta = Delta_Days( split('-',$begin), split('-',$end) );
my $intrvl = ceil($delta / $per);

print "begin:  ", $begin, "\n";
print "end:    ", $end, "\n";
print "per:    ", $per, "\n";
print "delta:  ", $delta, "\n";
print "intrvl: ", $intrvl, "\n";