How do I install f2py such that Sage won't give me the message in the description when I type %fortran?

Question

I am using Ubuntu 12.04. I get this error in Sage when I type %fortran:

error: f2py target file
'/tmp/tmplmbVQw/src.linux-i686-2.7/fortran_module_0module.c' not
generated

Traceback (click to the left of this block for traceback)
...
OSError: [Errno 2] No such file or directory: 'fortran_module_0.so'

Any help will be greatly appreciated.