with the rpm there is a script file in /usr/bin called idle. It contains the following:
Does this script work if you change the directory to the directory that you have idle.py in?
Another thing to try is to invoke idle through the python interpreter. Such as this (of course changing your directory to the one that idle.py is in):
I've have just finished installing eric3 an ide for python, which looks quite nice, but took a lot of effort to install, mainly because I didnt follow the instrucitons. If you follow the instruction precisely then it should work, but be aware that after installing pyqt there are some new libraries which the system doesnt seem to be aware of. Fixed this problem by doing an ldconfig.
Just a thought to fix your idle problem perhaps after compiling and installing python you may need to do an ldconfig as root.