Error 102 in FileMaker means that you're trying to add or update a field that doesn't exist in the database. Usually this happens due to a typo in the field name on your web form -- you'll want to check the names of all the fields you're submitting to on the form against the field names in the database. Things like spaces and misspellings are usually the culprit.

If you have a hard time tracking things down, try removing half of the fields (cut and paste half of the form into another text document) and submitting the form, and see if you get error 102. If you do, remove another half of the fields, and so on. Eventually you'll be able to find the problem field and correct the problem.