On my local box I believe the errors happen when attempting to starting an upload with > 7000 files in the library, but I could be mistaken - they might arise from searches or starting downloads. They're sporadic, with frequency increasing with number of files in the library. ~10000 files generates 10-20 such errors/minute, crashing the application within a few hours.

Not a startup problem, files are all indexed and shared and stable connections established.

This isn't a new 3.3.3 problem, nor does it appear to be a regression, I mention it only as I'd assumed the problems to be related to 100% CPU load with >7000 files previously.

There'll be a few dozen examples in bugs@, or shout if you'd like more specific tests, reports or setup info.