I think what you want is absolute days between two dates (the way any human would calculate). You can use following code. This will exactly give you 3 days. I have converted localtime to 12:00 am of the day and i am taking difference. It works :-)
use strict;
use Time::Local;
my $_timestamp1 = '1189669351';
my $_timestamp2 = '1189395751';
my ($sec1,$min1,$hour1,$mday1,$mon1,$year1,$wday1,$yday1,$isdst1) = lo
+caltime($_timestamp1);
my ($sec2,$min2,$hour2,$mday2,$mon2,$year2,$wday2,$yday2,$isdst2) = lo
+caltime($_timestamp2);
my $no_of_days = ((timelocal(0,0,0,$mday1,$mon1,$year1,$wday1,$yday1,$
+isdst1) - timelocal(0,0,0,$mday2,$mon2,$year2,$wday2,$yday2,$isdst2))
+/86400);
print "$no_of_days\n";