>I had previously found that article but it's not a fix for me (unfortunately). That article is really a guide for troubleshooting the initial installation of sql server. This is an established server with very infrequent, intermittent errors. Thanks though.

I changed my connection string from:

driver={SQL Server Native Client 10.0};server=TEST1;Failover_Partner=TEST2;database=testdatabase;uid=myusername;pwd=mypassword;

to

driver={SQL Server Native Client 10.0};server=TCP:192.168.0.10,1433;Failover_Partner=TCP:192.168.0.11,1433;database=testdatabase;uid=myusername;pwd=mypassword;

and this appears to have fixed the random error message.

For others with a busy sql server it seems leaving no ambiguity in the connection string solves certain intermittent errors.