Operation must use an updatable query ERROR

[wilestrade]

I have created a sql query to update data from one table to another table in an access database. But always getting an error message saying "Operation must use an updateable query".

I checked the file and folder permissions but everything is ok.

sqlString8 = "update pt SET cashamount = (SELECT pt2.cashamount FROM pt2 WHERE pt.jnlno =pt2.jnlno)";