Same problem here. It happens on a Dell Inspiron laptop and on a normal AMD 64 desktop, both WinXP32 with 2 GB RAM.
Looking at the circumstances, I suspect the freezes are related to the decoding phase, not sure though. Could also be a multi-threading issue, an infinite loop somewhere, or maybe a memory-allocation gone haywire, since the Alt.Binz process sometimes just disappears when these freezes occur... in other cases it just resumes downloading.
I'm expirimenting with the decoder sleep settings, not much improvement though. Also tried disabling logging & article-aging, didn't help much either. One thing I notice is, that during a freeze, the main window doesn't refresh. I tried collapsing all info-panes, hid as much tabs as I could (only queue, par and NLSS are open) ... nothing.
Weird thing is, that my desktop didn't have this problem with older versions (like the poster above).