Is this only happening on New Records?

If you have code running on the Form Close or Form Unload referring to a record that doesn't exist (because it's new and not saved to the table) you will get this error.

-Raymond

I think check to see if recorord is dirty and perform an undo. you may be trying to close a form before its saved.  
Undo
Dirty

To piggyback on Juan, or perhaps there may be some code looking for the ID of a deleted record, if you allow deletes.

I believe my Issue is when I am using Different Tables within the Form, just need to figure out how to do that without the error.

It sounds to me like you may need to use recordset.

That error usually means Access is trying to save or reference a child record that doesn't have a matching parent record.

For example, if you have a one-to-many relationship set up with referential integrity, you can't have an Order record without a Customer record, or an Order Detail record without an Order. If Access can't find the parent record that matches the foreign key value, you'll get an error like the one you're seeing.

Since the message specifically mentions HospitalContactID, I'd start by looking at any tables, subforms, combo boxes, or code that reference HospitalContactT. Make sure you're not creating or saving a related record before the corresponding HospitalContact record exists. Also check any form events (Before Update, After Update, Close, Unload, etc.) that might be trying to save data to another table.

If you're using multiple tables on the same form, as you mentioned, that's likely where I'd focus my attention. Verify that the records are being saved in the proper order and that all foreign key values point to valid parent records.

See: Widows & Orphans

Yes I think what was happening, I would put some info into my form and not complete the form, so when I was stopping to chek, I was actually creating an issue. If I put all the info into the form, filling out all the fields and then check it, works fine. Thanks for all the comments and help.