SL3 to SL5:UriMapper broke

I am working on the upgrade of my Silverlight application from SL3 to SL5.  All worked until I clicked on a link and got this error:

Page not found: "/ImageGallery/oid/241d9046-66c3-48da-a2ac-b2f61027ac95"

When I run it in the debugger, there is an exception that is caught, when I let it run through, I get the Page not found error.  The exception is:

Cannot find a Resource with the Name/Key NodeDataSource

Here is the UriMapper:

<uriMapper:UriMapper><uriMapper:UriMapping Uri="" MappedUri="/Views/Category.xaml"/><uriMapper:UriMapping 
		Uri="/ImageDisplay/{oid}/{galleryName}/{imageName}/{dspName}/{imageIndex}/{selected}/{totalCnt}/{piq}" 
		MappedUri="/Views/ImageDisplay.xaml?oid={oid}&amp;galleryName={galleryName}&amp;imageName={imageName}&amp;dspName={dspName}&amp;imageIndex={imageIndex}&amp;selected={selected}&amp;totalCnt={totalCnt}&amp;piq={piq}"/><uriMapper:UriMapping 
		Uri="/ImageGallery/{oid}/{pageIndex}/{imageName}" 
		MappedUri="/Views/ImageGallery.xaml?oid={oid}&amp;pageIndex={pageIndex}&amp;imageName={imageName}"/><uriMapper:UriMapping
		Uri="/CartImage/{index}"
		MappedUri="/Views/CartImage.xaml?index={index}"/><uriMapper:UriMapping Uri="/{pageName}/oid/{oid}" MappedUri="/Views/{pageName}.xaml?oid={oid}"/><uriMapper:UriMapping Uri="/{pageName}/reason/{reason}" MappedUri="/Views/{pageName}.xaml?reason={reason}"/><uriMapper:UriMapping Uri="/{pageName}" MappedUri="/Views/{pageName}.xaml"/></uriMapper:UriMapper>

In the SL3 code, the 3rd to last mapping, /{pageName}/oid/{oid} converted the url to /Views/ImageGallery.xaml?oid=241d9046-66c3-48da-a2ac-b2f61027ac95

Any thoughts as to the issue here?