I was able to make this work with Date::Calc. Like so: 
#!/usr/bin/perl -w
#mercury.pl-how old am I in Mercury Years.
use Time::localtime qw(localtime);#also for ctime
use POSIX;                          #for floor
use Date::Calc qw(Delta_Days);

#length of Mercury year in earth days
$mercuryRevolution = 87.97;

#get birthday stats for Oct 1, 1977 
$birthDay = 1;$birthMonth=9;$birthYear=1977;

$daysAlive = Delta_Days($birthYear,$birthMonth,$birthDay,
                        localtime->year()+1900,localtime->mon(),
                        localtime->mday());
$mercuryYears = POSIX::floor($daysAlive / $mercuryRevolution);

$nextMercuryBday = $daysAlive % $mercuryRevolution;
$nextBirthDate =  ctime(time()+ ($nextMercuryBday *24*60*60));
#strip hours,minutes,seconds from ctime string
$nextBirthDate =~ s/(\w+\s\w+\s\d+)(\s\S+\s)(\w*)/$1,$3/;

print "\nYou are ".$mercuryYears." Mercurian Years old",
      "\nYour next Mercurian Birthday is in " . $nextMercuryBday . 
      " days\n", "on ". $nextBirthDate;

[download]
It's a shorter program and it would even work for Dracula, now.

In reply to Re: Older people should know their age on Mercury by thunders
in thread Older people should know their age on Mercury by thunders

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