plus net snow leopard

Plusnet internet will not work on Snow Leopard.

Whats happens

1. It recognises Plusnet on either Wifi or via the Ethernet cable.
2. When "Connected" my applications stop responding and basically crashes Snow Leopard (including Finder an the toolbar)
3. I have to switch it off using the power button.

My system

• Macbook Pro 13" 2009
• 8GB RAM
• Partitioned 750GB Hybrid HHD
  • Lion partition
  • Snow Leopard
  • Data partition (for sharing)

What I have tried

• I have called Plusnet and they say its a problem Apple have and not them etc. fr@%ing wonderful! (even though I've ONLY experienced this with Plusnet).
• Running on the Lion partition – this works fine.

I don't really know how to fix this. So any help would be much appreciated

– Matt