Update current version on AWS Elastic Beanstalk

I have a python (Django) application on Amazon AWS using Elastic Beanstalk.

It's all ok, and my server is ok with my last application version. Now I have to update a file into my application so I followed this steps:

• I downloaded last app version from Application Versions section. I download the corresponding file zip.
• I edited my file from this version and I created a new file zip (this result file zip is the same of the original with my file edited).
• When I upload and deploy this new version of file zip I obtain this error:

ERROR Your WSGIPath refers to a file that does not exist.

Please note that I have not changed the files in the hidden directory .ebextensions and this directory is present in the new zip file.