Errors with v1.6.0

Those errors will happen until you perform the POST UPGRADE steps. There are FIVE post upgrade steps in the Install & Upgrade doc. Its mentioned in SEVERAL PLACES that you should ALWAYS READ the Install and Upgrade Doc for IMPORTANT Post Upgrade Steps.

AMS 1.6.0 Beta 1: Admin CP >> Applications >> AMS >> AMS Options >> SAVE (Do this for ALL 9 AMS Option Groups!)
AMS 1.6.0 Beta 1: Admin CP >> Applications >> AMS >> AMS Rebuilds >> Run all the rebuilds (thumbnails optional)
AMS 1.6.0 Beta 1: Admin CP >> Applications >> AMS >> AMS Permissions >> Set all the new permissions that have been added
AMS 1.6.0 Beta 1: Admin CP >> Applications >> AMS >> AMS Options >> Set all the new options that have been added
AMS 1.6.0 Beta 1: Admin CP >> Applications >> AMS >> AMS Categories >> Set all the new category options that have been added

You have not completed the first Post Upgrade Step as the only way that error would come up is if you had not run it yet. As soon as you perform the first post upgrade step, those particular errors will stop as the new indexes will be saved.