Created Issue: AjaxControlToolkit SliderExtender Control [27121]

I am using SliderExtender control using AjaxControlToolkit.dll. I am facing an issue:

Sys.ArgumentException: Please set valid values for the height and width attributes in the slider's CSS classes Parameter name: element size

Can anybody please suggest anything on this.
This is how my control looks like:
<ajaxToolkit:SliderExtender ID="SliderExtender1" runat="server" Enabled="true" EnableHandleAnimation="true"
BehaviorID="Slider2" TargetControlID="Slider2" BoundControlID="Slider2_BoundControl"
Orientation="Horizontal" Length="176" RailCssClass="sliderrail" RaiseChangeOnlyOnMouseUp="true"
Decimals="2" HandleImageUrl="/Includes/images/Product-Range/sliderImg.png" Minimum="0"
Maximum="103" Steps="103">
</ajaxToolkit:SliderExtender>
<asp:TextBox ID="Slider2" ToolTip="Slider" runat="server" AutoPostBack="true" Text="0" OnTextChanged="Slider2_TextChanged" />
<asp:Label ID="Slider2_BoundControl" runat="server" CssClass="SliderLabel"/>