Errors after update to latest version

yesterday i updated my piwik from 2.15 to latest version (3.2.0) and also update from php 5.3.8 to 7.0.3.
MySQL version: 5.6.22
running on windows server 2008, IIS 7.5

after the update nothing is working, i get errors
"oops… there was a problem during request. Maybe the server had a temporary issue, or maybe you requested a report with too much data. Please try again. if this error occurs repeatedly please contact your piwik administrator for assistance"

similar to After upgrade to 3.1.0 getting "Oops… there was a problem during the request." in Visitors real time widget · Issue #12051 · piwik/piwik · GitHub but with almost all the widgets.

any idea how to fix this?
maybe php/iis configuration


You can check here for the solution:

(delete piwik/plugins/UserCountry/LocationProvider/Default.php)