your main.php config file containing the Url manager rules
c) an example of the parameters you are passing to createUrl, like $this->createUrl(‘myModule/myController/myAction’, array(‘id’ => 1))
d) the Url that is being returned by this call.
With that information we are more likely to be able to see where the problem lies. From what you’ve said so far, I would guess that Url rewriting is working (since index.php is taken out of the Url), but maybe whatever link you are trying to make doesn’t find a corresponding rule in the Url Manager.