I have figured out the problem..in case anybody else is experiencing this issue:
In selectionWidgetUtil.as there are two functions (getGraphicsExtent() and zoomToSelectedFeatures()). Inside each of these functions there is a block of code that deals with creating a new extent around a single point, to allow zoom to selected features when only one point is selected. Inside these code blocks, a new extent is created (called result or graphicsextent).
When the new extent is created, the original code read : [graphicsExtent = new Extent(myPoint.x + 50000, myPoint.y + 50000,myPoint.x - 50000, myPoint.y - 50000, null);] where myPoint is the selected feature. However, when a new extent is created, the proper syntax is: [ new Extent(xmin, ymin, xmax, ymax, spatialReference)] NOT [new Extent(xmax, ymax, xmin, ymin, spatialReference)].
I simply changed the code to read : [graphicsExtent = new Extent(myPoint.x - 50000, myPoint.y - 50000,myPoint.x + 50000, myPoint.y + 50000, null);] and the problem is solved!