Sliders with -100 to 100 range problems

Hi,

I have multiple sliders inside a jQuery accordion control.  I'm using custom CSS for the slider rails and handles.  Problem is, when I try to move the handle, I get an error:

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

Then the sliders are replaced by the Slider textboxes and I get a NullReferenceException.

I don't need to change slider values using textboxes, so I don't want the textboxes to show at all.  It seems like it is not allowing negative values for the sliders.  But I need the range from minus 100 to positive 100.

Here's a sample of my CSS:

<style type="text/css">
.croplandhandle{   
    position: relative;
    height:24px; 
    width:17px;  
}
.croplandrail{
    position: relative;
    height: 20px;
    width: 200px;
    background: url('images/sliders/cropland_rail.png');
    border-radius: 8px;
}
</style>

Here's a sample of my slider inside an accordion:

<div id="divLulcSliders">
                    <div style="text-align:left">Cropland</div>
                    <div style="text-align:center"> 
                    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
                    <Triggers>
                        <asp:AsyncPostBackTrigger controlid="CroplandSlider" eventname="TextChanged" />
                    </Triggers>
                    <ContentTemplate>
                        <asp:Label ID="CroplandSlider_BoundControl" runat="server"  AssociatedControlID="CroplandSlider" />
                        <asp:TextBox ID="CroplandSlider" runat="server" AutoPostBack="True"
                             BorderStyle="None" Text="0" TabIndex="500" OnTextChanged="CroplandSlider_TextChanged" >
                        </asp:TextBox>                   
                        <ajaxToolkit:SliderExtender ID="CroplandSliderExtender" runat="server"
                            BehaviorID="CroplandSlider"
                            TargetControlID="CroplandSlider"
                            BoundControlID="CroplandSlider_BoundControl"
                            Minimum="-100"
                            Maximum="100"
                            Steps="1"
                            RailCssClass="croplandrail"
                            HandleCssClass="croplandhandle"
                            EnableHandleAnimation="true" 
                            RaiseChangeOnlyOnMouseUp  ="true"
                            HandleImageUrl="~/images/sliders/corn_handle.png">
                    </ajaxToolkit:SliderExtender>
                    </ContentTemplate>
                </asp:UpdatePanel>
      </div>

Appreciate any assistance.