Upgraded from 7.2.1 to 7.5.3 - now Dashboard will not load

I upgraded a sandbox instance (exact copy of production) from 7.2.1 to 7.5.3. The sandbox instance seems to work fine. I did the same in production and i keep getting “There was an error processing your request, please try again at a later time. - If this error persists, please have your administrator disable Ajax for this module”

The only thing that seems to get rid of this is to reset the users (my) home page - which wipes out all of my dashlets. After resetting, i decided to recreate my dashboard - just using standard dash lets - and BAM same error. I don’t relish tracking down one by one which dashlet is causing the issue, nor do I want to reset 40 users dashboards and manually recreate them.

Any suggestions?

More information - the issue occurs when adding any chart dashlet’s to the dashboard (specifically outcome by month or pipeline). Once its been added, you must reset the home page in the users profile to get rid of the error.