If you are not using Python 2.1 or higher you don't 
need to upgrade your PyClimate 1.1 installation.
No new features have been added since 1.1 release,
just the support for the newer versions of Python.

The key of the problem comes from the comparisons
of a python object with the None reserved word.
From Python 2.1 comparisons like:

if object == None:
  ...

are no longer valid. They have been substituted by:

if not object:
  ...

This change in Python behavior made the PyClimate 1.1 
release crash when executing some modules. Concretely,
the debbuged modules have been:

pyclimate.readdat
pyclimate.LanczosFilter
pyclimate.ncstruct

----
Please, remember that any bug detected while using PyClimate
can (and should) be reported to any of the authors of the 
package.

Thank you.