Flash movies are showing up 1/2 size in IE

In all versions of IE with which I can test (6, 7, and 8), my flash movies are showing up about half the size I specify. Sample code:


Event.observe(window, "load", function() { flashembed("video_container",
{ src: "/~dball/southwestern/flowplayer/FlowPlayerDark.swf", width: 400, height: 400},
{ config: {
playList: [
{ url: "/~dball/southwestern/uploads/assets/barsandtone.flv.jpg", type: "jpg" },

{ url: "/~dball/southwestern/uploads/assets/barsandtone.flv" }
]
}
}
) })

I confess this is unlikely to be a flowplayer problem, but I'm completely at a loss as to what might be going wrong. Does anyone have any suggestions? It works great in Firefox and Safari. For what it's worth, I get the same issue if I embed using swfobject or the like.