From Chris Sawyer´s page (Thanks now inc):
Despite successful compatibility testing of the Beta build of Loopy Landscapes under Windows 2000, somehow a bug crept into the code between Beta and the final build which prevents the game running under Windows 2000. Because Windows 2000 compatibility isn´t supported by the publisher, the final build didn´t undergo any Windows 2000 testing, and the bug doesn´t manifest itself under Windows 95, 98, or ME. After all the effort which was put into making Loopy Landscapes ´unofficially´ fully Windows 2000 compatible this is a real shame - This situation should not have happened. However, an updated build (V1.20.013) is now in production and anyone experiencing problems with the first build can obtain a version update patch from Hasbro Interactive. This patch also fixes another bug which can prevent guests entering the park in later years.