Sometimes it seems difficult to apply colour ramps.  This is the response of the software deevloper
the problem is that the properties settings are quite sensitive to the order you do things. If you do the following in the order listed you should be okay:

  1. Open properties window and select colour ramp tab, but with the option "use standard style" selected (which means single colour)
  2. Select layer to be edited (if this layer is already selected then select a different layer and then come back to selecting the required layer).
  3. Drop down list of attributes should be visible - select which to use to define colour ramp
  4. Click the button to update the colours in the colour ramp ("Update Colour Ramp" - change settings accordingly, i.e. select no.of steps, select start and end colours (don't forget to hit the evaluate button after this before applying colour ramp)
  5. Finally click the option to switch from use standard style to use colour ramp (check that the layer is not set to 100% transparent - some shapefiles are in the default view and this will mean you won't see the changes applied)
  6. Sometimes you may need to pan the map view slightly to refresh the map and implement changes.