[eluser]gtech[/eluser]
If I was in your shoes start from basics, as what you have provided looks ok.
create a fresh controller and model
then create a method in the model that just has the line echo "hello";
then load and call the method from the controller.
you can then satisfy your self that you can load models correctly.
My suspicion is that your model has php5 specific code (maybe you are using a php4 reserved word) in it somewhere and so it is not loading, turn your log_threashold on to 4 by setting the config parameters and see if you get any clues in the log.