Error 3022

[vcapy]

When I use a record lookup combo box to choose a record to
edit on a form, a runtime error appears occasionaly only
when I pull up certain records which reads " The changes
you requested to the table were not successful because
they would create duplicate values in the index, primary
key, or relationship. Change the data in the fields or
fields that contain duplicate data, remove the index, or
redefine the index to permit duplicate entries and try
again."

Then anohter error will appear if I try to bypass it and
it reads "Update or cancelupdate without addnew or edit."

There are no dupliate values in the index or primary
key.