At what point are you getting the error? the first boot, or after trying to install a PAT file? If it's the later, then it's because the install process of the PAT is writing over parts of you boot drive and messing it up. Some people get around this by making a copy of the boot drive before you try to install a PAT, then replace the messed up one by the PAT install with the unbroken copy you made. If it's the initial boot I dunno what to say.
I been playing with gnoboot's boot images and they work pretty nice, at least for testing purposes. I haven't testing any of the other boot images on here, but his doesn't get grub errors after installing.
It happens after i install the PAT file. Every time I replace the VMDK with the backup it boots up again but when i run Synology Assistant it shows Configuration lost and puts me put me back to where i started with the PAT. Is there i special way to do this in ESXi because in Virtualbox i don't have these issues