Last weekend our server administrator upgraded our ePO from 4.5MR5 to 4.5MR6, then up to 4.6 and finally to 4.6MR1. I don't have details on the exact steps he took or any issues found.
the "exact stepd taken" would be the information that would be most important ;-)
But check this: Maybe he just forgot to checkin the latest extensions (e.g reporting extension) in ePO? you usually could check for updates under "software manager" (that was not available in v4.5 I think).
We found the answer:
ePO would only display queries with TABLE as a result. All other results such as pie chart, line chart and so on would give the error.
This was due to permissions on the \Program Files (x86)\McAfee\ePolicy Orchestrator\JRE directory not having the right permissions. The admin didnt' specify the account missing the right permissions but everything is working now. Just putting this for any future reference.
Meforum: I wish. Our admin hides in a closet we're not allowed into