By reading lots of links and finally got mine working.

My issue was connected to a 32bit Access database from 64bit SQL server running as a job and it throw Code: 0xC0202009 , Error code: 0x80040154 and "Class not registered".

For debugging, I changed the debugging option "Run64BitRuntime" to False.

To fix the scheduled job with package saved in SQL server, I modified the step to use the 32bit DTExec.exe and as Type of Operating Ssystem (cmdExec) to be something like this

"D:\Program Files\Microsoft SQL Server (x86)\90\DTS\Binn\DTExec.exe" /SQL "\packageNameInMSDB" /SERVER CQDSC01 /MAXCONCURRENT " -1 " /CHECKPOINTING OFF /REPORTING E

http://msdn.microsoft.com/en-us/library/ms162810.aspx - Great link for dtex.exe