XAMPP/utilities — Issue #1: osType.ordinal()
Author: tomass1996
Created: 2012-01-19 04:49:12+00:00
State: open

The range is 0->3 not 1->4
So this causes issues meaning on windows it tries to use the path:
Drive:\Documents and Settings\User\.minecraft\lastlogin
instead of:
Drive:\Documents and Settings\User\Application Data\.minecraft\lastlogin