Ok, I've identified one problem in the sample of script you pasted in above.
The last port signal, ETSignalProbe, is never presented using your syntax. Remove "replace()" from around probe_left as as follows:
/ stimulustimes = [1 = ETSignalFixation, fixation_pic; 300 = ETSignalFixation, fixation_pic_red; 500 = blank; 517 = ETSignalFaces, angry_pic_left03, neutral2_pic_right03; 1017 = blank; 1034 = replace(probe_left), ETSignalProbe]
Let me know if that fixes your issue. If not, please email the whole script and media files to inquisit at millisecond, and I'll take a deeper look.
Thank you for your help. I've attempted the change that you suggested but it hasn't made any difference. That is, parallel port signals are still not being sent when I run the experiment in Inquisit. I've just e-mailed you the experiment files, including the pictures. Please let me know whether you have received this. I look forward to your reply!
To anyone concerned:
This issue was resolved in a minor bug fix. The issue was resolved by downloading the very latest build of Inquisit 3.
Thanks to Sean for updating the software so quickly and to Dave for providing the background info!