Rewinding and/or seeking html5 video raises INDEX_SIZE_ERR

[jabbascript]

I'm writing an application using Qt 4.7 and QtWebKit that displays a video. I'd like to add a stop button that stops the video and rewinds to the beginning. Whenever I try to set the video currentTime = 0.0 it raises an INDEX_SIZE_ERR exception. I can read currentTime just fine and the values are correct and I can also pause / play the video however any attempt to seek the video, even back to the beginning, fails.

Here is the relevant code:

@
<video id="lionvideo" src="video/lion.mpeg" preload="auto">Foo</video>

<script>
function playPause() {
var myVideo = document.getElementsByTagName('video')[0];
if (myVideo.paused)
myVideo.play();
else
myVideo.pause();
}

function rewindVideo() {
var myVideo = document.getElementsByTagName('video')[0];
try {
myVideo.currentTime = 0.0;
}
catch (err) {
alert('Error: ' + err);
}

</script>

<input type=button onclick="playPause()" value="Play/Pause">
<input type=button onclick="rewindVideo()" value="Rewind">
@
The video is being loaded from a local file on my hard drive and has had plenty of time to load.

Thank you for your help.