Python on Eclipse, Ant file not found

Hi i am not sure do i suppose to ask on here, but i guess it is python related. I am running Python on Eclipse with Pydev,
When i chose the file for python interpreter under preference, it gave an
error:Python stdlib not found or stdlib ound without .py files. It seems that the python /lib folder(Which contains the standard library) was not found/selected during the install process or the stdlib does not contain the required .py files (i.e only has .pyc files).... etc and what do you want to do, i chose to process anyways.

When i open new file, i cant choose python, so i chose PyDev & Module, but when i run the codes, any codes, it ask for select what to run there are 2 Ant Build, and either one that i choose, it says Build Failed, Reason: Unable to find an Ant File to Run..... what does this mean?

I have totally no idea what it is happening and what to do.
Please help