[AccessD] Possible Causes for #ERROR# in datasheets fields.

Hello,
 Occasionally, the user will be entering data, and when moving (Tabbing) to
another field they are getting this #ERROR# across all the fields in a
datasheet. Sometimes they are getting this error along with an msg about
someone else has change the current record, but there would be no other
users in the system.

 The only way to get the error to go away is to close the form and re-open.
After which, there is no evidence of any problem.

 It was noted, that is seems to happen more, when the user is entering the
first record to the datasheet dataset.

A2K Split FE/BE

Any Clues?