I'm having issues too, with running a custom report. Most times the query just times out. I'm doing some database work this week, I'll try to find some ways to optimize it, but I'm not too familiar with uc_reports so I don't know where to start tweaking code.. yet.

It also seems to get worse when there is a month that ends in the middle of the week, and you try to get a report for that week. (If you're able to get to the Custom Reports page).