The page flow is pretty standard. If parameter indicates a new record, defaults for the field are set. If not, I look for $_POST for the fields and use them. If they are not there, I load from the database.
Don't think it's data access rights because other forms update OK and all use the same DB connection. Might be memory limit or other setting of some kind on the server, but that's over my head.
Generally, has anyone seen this before? It's new to me and I could use some help. I can cut/paste some of the relevant code if you can point me to what may be relevant.