Question : Problem: Cluster manager redundancy

Hello,
My company has two servers running windows 2003 and Sql 2005.  These boxes are being hosted at a local hosting company.  Currently, the servers are set up as a cluster.  Each box has three nic cards.
The first card (Front end - Public ip) the second ( back end - private ip) third ( heartbeat).  We have tested this redundancy many times by powering down the first box and like clock work it switches to the second box.  
We had a situation yesterday that made the redundacy fail.  Our front end card became disabled ( for lack of a better word) and the box was taken off line.  The redundancy did not work because the heartbeat was still working??  
So my question is - is there something wrong with the way our hosted company set up cluster manager on these servers?  Is there a better way??
Thanks for your time

Answer : Problem: Cluster manager redundancy

Exactly what did you mean with "[the] card became disabled"? If you have an IP resource in the SQL group, and this IP address fails because it can't bind to the (disabled) NIC anymore, then you should have had a failover.