Want you install Python 2.7 to run a Google App Engine server on your old RHEL 5.2? I can just say that it was impossible for me from the sources. Hopefully, I find a excellent blog post which gives an alternative install script. Just download and run it. It will download and install Python 2.7.2 and its commons dependencies. The only limit I know is that you cannot Python based apps with GUIs because it's not compiled against TCL/TK.