We're actually seeing the same errors as well after our upgrade from 4.1 to 5.0 U2 in the past 2 weeks. Same as you, all of our rollup jobs are working fine and there does not seem to be any performance issues. We also have our 5-min stats turned up to Level 2 so that VKernel can pull the proper stats for its reporting. I'll be opening a case with VMware today. I'm wondering if they didn't jack up their rollup jobs like they did in the 4.1 upgrade. There's a KB article out there somewhere that talks about how to fix those... maybe the same thing has happened here. I'd suggest you do the same since the number of issues reported for the same problem make a big difference to support.
I'll update this thread when I know something else.