SSIS Package Failing On Start- HELP!!!

Hi, Forum: PLEASE HELP ASAP!
I set up a simple SSIS package via the Import/Export wizard, saved with "DoNotSaveWithSensitvePW", scheduled it as a job.
And whether it runs through the scheduled agent, or I invoke it manually, I get this error:
Description: Failed to decrypt protected XML node "DTSassword" with error
0x8009000B "Key not valid for use in specified state.". You may not be
authorized to access this information. This error occurs when there is a
cryptographic error. Verify that the correct key is available
I've seen a lot of confusing google hits, that talks about proxies, etc. so, I need exact steps 1,2,3....etc. The account(s) I use are sysadmin.
Await reply!

Check the following blog is useful...
http://vittoriop77.blogspot.com/2007/07/failed-to-decrypt-protected-xml-node.html

Many thanks, Mohammad! I will try this (the only thing I haven't tried) and post back results.
In the meanwhile, I tried this with no success:
http://www.codeproject.com/KB/aspnet/Schedule__Run__SSIS__DTS.aspx

The only thing I couldn't/didn't do is set up the credential for a WINDOWS account. I can only use SQL Authentication here. Is this a necessity? Not sure if this is just the author's example. Please advise, THANKS!

Hi, i tried your suggestion and so far no good. I forced the job step to go back to using the SQL Server Agent account instead of proxy.
Could not find file 'Cocuments and SettingsmyprofileLocal SettingsTemp mp32.tmp' Why they're lkg for temp file I don't know.
When I force it to use my setup proxy, it says cannot find data for proxy. H-E-L-P!

thx, Satya. I am storing/running the package from SQL Server - is it a requirement that I run from file system? Otherwise, what folder would I give proxy permission? Can you list steps? Regards!