Error Upgrading ESXi 5.1 U1 to 5.5 U1 (or 5.1 U2, same error) - Could not parse VIB XML, 100-digit error code

Hi,

today is the first day in my VMware life that I ran into an error whilst trying to upgrade with CD at the server ... as I was suspecting a wrong image I tried both the HP and the standard images - same error.

Unfortunately neither the VMware KB or Google gave me a hit on searching ... but maybe you can give me a hint :-) (ok, honestly I didn't enter the 100-digit error code).

Cheers!