Your error indicates issues with your analytics index.
First of all (something to do whenever you have errors after an upgrade):
make sure all your files are actually from the correct new version! Verify your bin folder and the Sitecore configs: they have to match with a clean version of the required Sitecore (in this case 8.0 - update5).
If you verified that and the error is still present, check if your upgrade process was completed.
The upgrade guide does mention some steps to take to finalize the upgrade, so make sure you did those:
To upgrade your solution from the initial version of Sitecore, 8.0
rev. 141212, you must update the social profiles data to ensure that
it is compliant with Sitecore 8.0 Update-5. To update the social
profiles data, open the following page:
- Redeploying Marketing Data
To update the marketing data to ensure that it is compliant with
Sitecore 8.0 Update-5, open the following page:
http:///sitecore/admin/RedeployMarketingData.aspx (make sure
that analytics is enabled)
- Rebuilding the Reporting Database
As part of the upgrade process, you must also rebuild the Reporting
That rebuild of the reporting database is the only way to fix issues with your analytics index (what seems to be the case here). More info on how to do this: https://doc.sitecore.net/sitecore_experience_platform/setting_up_and_maintaining/xdb/server_considerations/walkthrough_rebuilding_the_reporting_database