Runtime/PLCObject : move call to PreStartPLC right after call to the "start" method of all python extensions, and then just before the start of the python loop executing python_* blocks.
from __future__ import absolute_import
from etherlab.etherlab import *
from util.BitmapLibrary import AddBitmapFolder
import util.paths as paths
AddBitmapFolder(os.path.join(paths.AbsDir(__file__), "images"))