If it's saying "cannot execute binary file" then that's Linux speak for "I don't understand how to run that" and it probably means: "you're trying to run an x64 binary on an x86 install".
Hmm... My computer is a 64 bit machine, and my Ubuntu 13.04 is also the correct 64 bit version. It can't be anything to do with that?
I'm a bit unsure on this but perhaps the problem is being caused by running Ubuntu from a USB stick, or something like that. It's really difficult for me to do this root because the persistence on the USB doesn't seem to work; so every time shut down the computer i have to copy the files back over to the Ubuntu USB when i switch back on again.
Is it okay if the Hudl doesn't show up in the file explorer, while in flashing mode? I can't help feeling that might have something do with it also.
And, do i need the Android SDK installed?
Someone really needs to make a tutorial to make this whole process a heck of a lot easier! For people like me who have little experience with Linux, this root is a complete nightmare...