I created a simple SSIS package to copy a table from one database to another.   The source and destination connections used SQL Server authentication.  

When I tried to run the package in an SQL Agent job I received an error message:  [DTS.Pipeline] Error: component "Source - History" (1) failed validation and returned error code 0xC020801C.

Here was the fix for me.  When I imported the SSIS package to Integration Services, I set the Package Protection Level to “Rely on server storage and roles for access control.”

These links helped in solving the problem: 
 

http://support.microsoft.com/kb/918760
http://msdn.microsoft.com/en-us/library/microsoft.sqlserver.dts.runtime.dtsprotectionlevel.aspx
http://www.codeproject.com/KB/aspnet/Schedule__Run__SSIS__DTS.aspx