wrt your comment "I've reproduced your steps without any problems, and uploaded VMware-VMvisor-Installer-5.5.0-1331820.x86_64.iso and created a new host upgrade baseline. That baseline I attached to a host running 5.0.0 1311175. I then remediated the host, and it went from 5.0 to 5.5 without any problems. So I'm not sure what went wrong in your case, but it can't be much. Perhaps you could try again or let me know the steps you took."
I tried again & strangely same issue, here is what i did :-
1. Fresh install of esxi 5.0
2. went to update manager - esxi images tab - upload the same & below error ...
3. I uploaded a patch even that failed ... let me explan that too but lets guess what is the issue here ..
Pls suggest what could be reason ...
