upgrading with vsphere update manager

hey guys,

I have the following setup:

- vCenter Server Version 5.1.0 Build 880146

- vSphere Update Manager Version 5.1.0.13071

- ESX(i) Version 4.1.0 (260247)

--> the vCenter Server is running on a vm within the esxi host...

I now want upgrade the esxi server and therefore downloaded VMware-VMvisor-Installer-5.0.0-469512.x86_64.iso.

When trying to upload the .iso to update manager I get the following error message:

"Failed to import data. The uploaded upgrade package cannot be used with VMware vSphere Update Manager."

Very confusing stuff... hope you can help me with that...

thanks in advance!