XAML Error

Hey,

I have a button style in XAML that is working fine for me, but when testing the application on another computer it gives me the following error:

'System.Windows.Baml2006.TypeConverterMarkupExtension' threw an exception.'

And it says it is on the second line of this:

<Storyboard x:Key="Timeline1">
                    <DoubleAnimationUsingKeyFrames BeginTime="00:00:00" Storyboard.TargetName="glow" Storyboard.TargetProperty="(UIElement.Opacity)">
                        <SplineDoubleKeyFrame KeyTime="00:00:00.3000000" Value="1"/>
                    </DoubleAnimationUsingKeyFrames>
                </Storyboard>

Any Help Please?