I have a command button that executes many different subs. It will not
execute the following sub (written inside sheet13(summ)):

Sub SummAddTextBoxHeaders()

'TPTB
Sheets("Summ").Activate
ActiveSheet.Cells(56 + (TPTB.Height - 66) / 12, 1).Select
With Selection
.Value = "Tech & Proj. Data Project Engineer Summary:"
.Font.Bold = True
End With

End Sub

It gives the following error:

Run-time error '-2147417848(80010108)':
Method 'Run' of object '_Application' failed

I can run it by stepping through it with no problems. The offending line
when using the command button is:

ActiveSheet.Cells(56 + (TPTB.Height - 66) / 12, 1).Select

(If I comment this line and the ones below it, I have no problems.) I have
tried placing the routine in other locations with no success. Any help would
be greatly appreciated. Thank you.