using prior response as stimulus

Hi, I would like to use the subject's reponse in a previous trial as a stimulus in the next trial. Below is what I did according to the online tutorial, however something doesn't seem to work. Please let me know what I should do to make this work.

e.g. The possible responses in trial 2 are q, w, e, and r (rt: 16,17,18,19).
If the subject responds with 'q' ([I]or[/I] w/e/r) in trial 2, he/she should see one of the images under stimlist 'q.txt' ([I]or [/I]w.txt/e.txt/r.txt) in trial 3.
Accordingly I put '$=2' in the stim column for trial 3.
In trial 3, however, I do not get an image but simply a text-form stimulus ('Q').
All the images are under the relevant stim folder so it doesn't seem to be a problem with the path name.
Please help.



The location of the images are all under the relevant stim folder.

Can you post a zipped copy of your input file and a few stim so I can try to replicate the problem here?

Hi, this is my input file.
As you will see, each even-numbered trial uses an image file for a stimulus that is dependent on what the subject responds to in the previous trial.
The problem is with the 6th and 16th trials. I would like the images to be randomly chosen from one of the four stimlists, depending on the subjects' response in the 5th and 15th trials.
Hope you can help!

I'm looking forward to hearing back from someone... as I really need to get this problem solved soon.