Left it running for more then 8 hours, with no downloads. It was responsive, except for "library" tab, which takes forever to open (3-4 seconds, compared to less then 1/4 of a second for the other tabs). 19 files in the upload directory, should not be an issue..... No new errors in the log, from sitting idle a full day. It looks like the problem only occurs after some downloads have already occured, simply attached to the network is not an issue.

After the problem occurs, it does not matter if I kill all downloads and searches or not - java run time environment still takes 100% of the CPU and needs to be killed (task not responsive to normal window close command - maybe I did not wait long enough).