Can't add record in the form

[Malvina]

I have a form that allows user to view records for a
specific client. If I would like to add a record, I get a
message: "Can't add record(s); join key of
table 'tblMyTable' not in recordset." I had set the
properties of my form to:

AllowEdits - Yes
AllowDeletions - Yes
AllowAdditions - Yes
DataEntry - No

I am not sure what I can do about it???