The same thing happened to me yesterday.. JE 43 and 42 hung, 41 and Emplode (2.0b13) worked fine. After a whole bunch of trying to figure out what the problem was, I found I could close the progress window to get to the main JE window.. the All Music item was red because it was trying to fix something. Somehow I got it open (maybe by trying at the right time, I couldn't reproduce it again) and found that it had moved a folder there (presumably because it had no parent, or maybe I created a circular ref). It was named "Dire Straits".

So I went back to Emplode and searched for "Dire Straits".. it showed two results (the real folder, and an evil broken one), then hung before drawing the value for the length column. So I started again, turned off all the columns except Name and FID, searched again, and then I was able to delete that bad node and synch. All was well from there.

Sooo.. I think a bug in JEmplode 43 caused the problem somehow, but I unfortunately can't specifically tell you what.