You've a couple of mistakes:

1. When packing your temp value, you've written d262, when you should have used 'd262'. (use warnings would have caught that.)
2. If you want to perform math operations on your value, you need to unpack it to a number: See the unpack below.

$p = unpack 'v', pack 'H4', 'd262';;
print $p;;
25298

$y = (($p & 0xFE00) >> 9) + 4;;
$m = (($p & 0x01E0) >> 5) - 1;;
$d = ($p & 0x001F);;

print join '/', $y, $m, $d;;
53/5/18
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Note you might need to use 'n' instead of 'v' for the unpacking depending upon the endianess of the data:

$p = unpack 'n', pack 'H4', 'd262';;
print $p;;
53858

$y = (($p & 0xFE00) >> 9) + 4;;
$m = (($p & 0x01E0) >> 5) - 1;;
$d = ($p & 0x001F);;

print join '/', $y, $m, $d;;
109/2/2
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