Your leap year code is still wrong. It should be:

    if ($month == 2) 
    {
        if ( ( $year % 4 == 0 )         # normal leap year
         &&  ( ( $year % 100 != 0 )     # century year
               || ( $year % 400 == 0 )  # leap century
             )
           )
        {
            return 29;
        }
    }
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Also, you declare my $days = 0 but you don't use it.

Update: All those parens are ugly, how about:

if( 2 == $month )
{
    return 29 if 0 == $year % 4 and 0 != $year % 100 
                 or 0 == $year % 400;
}
[download]

That works thanks to short circuitry and precedence. (yeah I could remove the 0 != part, but I wanted to retain explicit readability.)

I think the leap year formula has become a frequently asked question, so I posted the answer here as well.

Update: Chromatic's code will now work. It a slightly different way to look at it, using if and unless, but it works.