macro doesn't work anymore

Hi all,

For some reasons this macro doesn't work anymore, I'm not an expert so I can't fix it. The macro has been programmed to work when the folder "Plough Log Processing" is placed in the desktop, directory "C:\Users\Processing\Desktop\Plough Log Processing", or else, when I run the macro I get right away the error:

ChDir "C:\Users\Processing\Desktop\Plough Log Processing"
Workbooks.Open Filename:= _
"C:\Users\Processing\Desktop\Plough Log Processing\Template - Plough KP xx.xxx-KP yy.yyy.xlsx"

The macro works the files within the folder in order to format the data and create a graph, I just have to make sure that the 2 files "Plough_Log_140911000008_NPOUT615-8.npd" and " kp000.139_kp023.755_140910151341_140911061356.nav " are within the right limits, and they are.
So if you run the 3rd macro in the list, the underlined in the screenshot, from the attached Template - Plough KP xx.xxx-KP yy.yyy.xlsx , and you give the correct kp limits, for this example, when prompted, you can insert "initial kp = 2.000 , final kp= 3.000 " at this point, the macro should work the magic and create the graph, but for some reason it gets stuck at this:

type mismatch

Range("G1").FormulaR1C1 = "=CONCATENATE(20,(MID(RC[4],12,6)))"
File_Date = Range("G1")

..... there something wrong with the range G1, but I'm not really sure what's the issue, as I haven't been doing anything different.

Please let me know if someone can help
thanks!
Alex