Providing feedback?

[Srdan]

I have been attempting to do this on my own but I am running out of ideas and time. I hope someone can give me an advice that would help with this.

I would like to present subjects with a set of pictures that will appear on the screen one at a time. They will be instructed that clicking on some of those pictures could be a beneficial thing. Therefore they will click on some or all of the pictures.
I would like pictures to advance from one to the next on “click” or after a specified time period if a person does not click on it. Also, I would like to give them a feedback if they click on a “beneficial” picture. This feedback should last a few seconds after which they should automatically be exposed to the next picture.

I tried using pop-ups as a feedback method and it works fine except subjects have to acknowledge a pop-up (click “ok” on it) and if they don’t do it fast enough error message appears (“run-time error 401 – can’t show non-modal form when modal form is displayed”).
Also, is there a way to have subjects press a space bar instead of clicking on images in order to advance from one to another and/or to select “beneficial” image?
Finally, I am currently using scale response and placing images as a background in order to be able to click on them. Would you suggest using any other method?

Thanks!