Issues with pulling/adding data in a subform

Hi all,

I created a subform that is supposed to pull data from cert(name, ID) and employee-cert(employeeid, date), which is an associative entity. I'm using the 2 column method to hide the cert ID's and show their corresponding names in the subform, but when I try to click an ID to create a new row I get the error "Form cannot be edited; It is bound to an autonumber field 'cert id'". I don't want to change the autonumber, simply select it without adding a new number every time something is selected.

Additionally, On another subform I have done the exact same thing and I am not getting that error, but when I make additionally changes and try to exit I get an error stating "The changes you requested to the table were not successful because they would create duplicate values in the index, primary key, or relationship". They wouldn't create a duplicate of anything because the employee hasn't yet be assigned to the client.