These errors are usually logged in the Agent Log or by the application when the SQL Server instance low on memory or the underlying storage is having some issues. You may find the below links useful.

http://sqlblog.com/blogs/merrill_aldrich/archive/2010/06/22/long-i-os-and-tcp-timeouts-are-not-a-sql-server-problem-except-when-they-are.aspx

http://social.msdn.microsoft.com/Forums/en/sqldatabaseengine/thread/1536b610-e548-40c1-b9d0-1be3ad19a823