VBA Code works with step (f8) not run <ctrl>f8

Hello All,
WIN 7 Excel 2010
I have some code that I can get to run by stepping through but not by running macro. HELP!

code is searching for slope of a linear trendline after making chart. When it runs it errors out at the line starting with XMARK because it has NOT written the equation for the line (.DataLabel.Text)

Worksheets("Graph1").Activate
    
With Worksheets("Graph1").ChartObjects(1).Chart.SeriesCollection(1).Trendlines(1)
    
    
    Worksheets("Graph1").Activate
    Worksheets("Graph1").Cells(25, 4).Select
    Selection.Value = .DataLabel.Text
    End With
        Worksheets("Graph1").Cells(26, 4) = Mid(Worksheets("Graph1").Cells(25, 4), 5, 100)
         xmark = Application.WorksheetFunction.Find("x", Worksheets("Graph1").Cells(26, 4), 1)
        Worksheets("Graph1").Cells(27, 4) = 1 * Mid(Worksheets("Graph1").Cells(26, 4), xmark + 4, 100) 'y-intercept
        Worksheets("Graph1").Cells(28, 4) = Mid(Worksheets("Graph1").Cells(26, 4), 1, xmark - 1) 'slope (IACF)

Thanks for anyone willing to help.