Converting site from 1.1 to 2.0 receiving element not known error.

Question

We are finally converting our site to .NET 2.0 and I'm having problems with the conversion.  I've got a class that was created and inherited from System.Web.UI.HtmlControls.HtmlTextArea.  I'm trying to use this as a control on another usercontrol defined as follows:

<technicolor:PixelTextArea  disabled="true" id="errorText" class="<%# errClassType %>"  CharWidth="6" CharHeight="14" runat="server"></technicolor:PixelTextArea>

So the error that I'm seeing is that PixelTextArea is not a known element.  This class is in the APP_Code directory and the control that I'm adding it to is a user control in another directory outside of that.

Any ideas how I fix this?