PNG files look like crap?

1

Hey, i have been working on flash for awhile, but i just started using png files with alpha channels, and everytime i publish them in a flash file they get a jagged pixel looking effect if viewed on particular machines, the site i am working on is not near done but check (www.troyblank.com) and look at the orange, my tube monitor with 256mb graphic card makes it look smooth without any jaggedness, the plasma screen with a close to identical 256mb card at work makes it look slightly jagged, i have no idea what is the cause of this, has anyone else experienced this?