Arcpy.mapping question

Hi all,

I'm having a bit of trouble with this. I'm trying to run a Python code in Pyscripter which at the end select a number of featureclasses in a gdb and adds them to a mxd that I select. The code runs without bringing up any errors but when I open the mxd it hasn't added any layers. The code I'm running is as follows:

I then add layers in the middle section of the code.

At the end of the code I then add:

But to no avail. Without it bringing up an error message would anybody have any idea what's going wrong?

Thank you,

Dónal