Checkboxes in shared worksheets

[C with no eyes]

I have used the form control checkbox in a shared workbook.

The checkbox is on an 'input' sheet. When a macro on the 'input' sheet is run, the data is then copied to the bottom of the 'record' sheet then all unlocked cells and checkboxes are cleared so the 'input' sheet can be used again.

It works when the sheet is locked but it doesn't work when the sheet is shared (when other users are allowed to make changes).

I am getting a run time error:
'2147024809 (80070057)' requested shapes are locked for selection.

It falters at this point:

    ActiveSheet.Shapes.Range(Array("Check Box 1")).Select    With Selection
        .Value = xlOff
        .LinkedCell = "Workings!$P$3"
        .Display3DShading = False
    End With

(I know this because it does all of the actions before this point)

Does anyone have any suggestions?

I have found:

[COLOR=#000000][FONT=Courier]    ActiveSheet.Unprotect Password:="password"[/FONT][/COLOR][COLOR=#000000][FONT=Courier]    ...OTHER STUFF...
[/FONT][/COLOR][COLOR=#000000][FONT=Courier]    ActiveSheet.Protect  Contents:=True, Password:="password"[/FONT][/COLOR]

(No, this isn't actually the password!)
Does this work in a shared sheet?

But I would rather have something like:

ActiveSheet.Shapes.Range(Array("Check Box 1")).Value = xlOff

Thanks.