missing dll error

when running the embedding_in_wx4.py available in the examples.zip i always get an error dialog that a wxmsw26uh_vc.dll is missing. Pressing ok button of the error dialog makes the program run as usual. When I modified the code and added the line “from pylab import *” the program does not give the nagging error dialog. Adding that line is a fix but I want to find out why the program needs this dll and how can I alter the code so that I will not use the “from pylab import *”.I use wxPython 2.7, Python 2.5 and Matplotlib 0.87.7