Do not use that widget anymore, it is not compatible with HTML output.
Why not just insert a text container (shape or caption, make it transparent) on the first slide, display it for the rest of the project and always on top. Insert the variables using the X button in the Character part of the Properties panel of the text container:
Slide $$cpInfoCurrentSlide$$ of $$cpInfoSlideCount$$
The advantage over having this on the master slide, is that the text container will have an ID which makes it controllable: you can hide/show it if necessary on some slides (like question slides, which have their proper progress indicator).
Be careful however: this will be dynamic text, generated on runtime. That means that you have to use a websafe font, to have it looked like static text. It depends on the output as well, but since you use a widget I suppose you are using SWF output. In that output all static text is converted to images, which allows you to use any other font even though it will not be available on the trainee's system. That is not the case for dynamic text