SAS has many proccedures that do probit model. I think your problem can
be analyzed with proc nlmixed proccedure. The procedure can deal with
panel(blanced/non-blanced) data + likelihood estimation with you
specified likelihood function. You can download the documents at,
look into SAS/STAT 9.1 User's Guide
If you can detail your problem + data structure, I am sure SAS nlmixed
gurus will help you out.
Happy New Year.