Cause:

Solution:

1) (Optional) Open the form in Design view:

a) Click the 'Forms' tab in the Database window.
b) Select the desired form from the list box. (The selected form is highlighted.)
c) Click 'Design'. (The selected form appears in Design view.)

2) To change the RowSource property of the chart:

a) Click once on the chart. (Handles appear around the chart.)
b) Select the 'View' menu and select 'Properties'. (The Chart <chart name> property sheet appears, where <chart name> is the name of the chart.)
c) Click the 'Data' tab.
d) Click in the 'Row Source' property box.
the Row Source property box
e) Type a valid RowSource property in the 'Row Source' property box.
f) Click 'x' on the upper-right corner of the property sheet. (The property sheet closes and the new setting is saved.)
g) Select the 'File' menu and select 'Save'. (The new setting is saved.)