B4 Demo question

I'm very interested in the B4, but I have had some problems with the demo.

My system is a 550Mhz PIII running Windows XP with a Echo Layla/20 audio device.

I seem to get good performance with minimal latency when I set the Layla buffer size very low (128 - 512 bytes), but after playing for less than a minute the Demo hangs up and produces a buzzing sound. The B4 demo will not work again until I reboot.

I'd like to consider purchasing the B4, but I need to know that it is reliable. Are there known issues with the Demo, or should I assume something about my system is to blame? I find it hard to believe that the product is generally this unstable.

Thanks for any advice.