Error sorting subform

Has anyone ever gotten this error message when sorting an Access Project subform based on an SQL table?

"column prefix [name of subform] does not match with the table name or alias used in the query".

I built a main parts form from a SQL table [Parts] using Access Project. I then added a subform [FSinvPARThistory] based on another SQL table [PartHistory] to record history for the part. The two are linked together using primary key 'ID'. I can sort the subform but then when I go to select another record on the main form I get the above error message.

Can you not sort a subform? If not, how can I prevent users from inadvertantly sorting a subform and getting the same message?

Thanks.

Open the subform and sort the resultset there.