.NET C# Csharp winforms and flash 8 transparency

Hello,
PROBLEM BACKGROUND :
very strange problem at hand atleast for my feeble mind, i have a c# windows form and a flash control (.ocx) on it , the flash file is published with wmode = transparent, and winform’s TransparencyKey is set to a magenta which causes magenta colored areas in flash to go transparent.

PROBLEM DESCRIPTION :

Everything was working fine , until i installed my project on another computer running Windows XP sp2, same code is working fine transparenting out magenta areas , but on some computers with same operating system (winxp) the magenta areas just stay there and im stumped why it so , can any one help please ? :cross-eye