Cannot Execute upgrade script on host- Error while upgrading esxi 5.1 to esxi 5.5

I was doing my ESXi upgrade from 5.1 to ESXi 5.5 from update manager. But I got struck with the error message as
"Cannot execute upgrade script on the host"

Steps I tried
Rebooted the host and again tried remediating the host from update manager, but didn't worked.

Solution

Finally it solved for me. I executed below given commands.Removed the FDM agent on the host and rebooted.

 

cp /opt/vmware/uninstallers/VMware-fdm-uninstall.sh /tmp
chmod +x /tmp/VMware-fdm-uninstall.sh
/tmp/VMware-fdm-uninstall.sh


Reboot the host now and again try remediating the host from update manager. These time it worked.

Removing the FDM agent from the host manually fixes the issue.