Moved machines to external drive and now they won't run

[Dmur]

Need help!

I have copied a few of the virtual machines that I have been working on in college on to a new external hard drive so I can work on them at home.

I have just tried to load a few of them up and I keep receiving the attached error message.

Is there anything I can do to fix this problem and have it up and running again or am I doomed?

Thanks in advance!