Error message: Java Virtual Machine

Ok, I purchased a game called Minecraft for my daughter this morning and have so far been unable to use it.

When we tried to download and run it, an error message appears that says:

'Error: Could not create the Java Virtual Machine.'
'Error: A fatal exception has occurred. Program will exit.'

I really do not have a clue what this means, I would really appreciate any help or advice. I'm not technically minded at all so please go easy on the jargon!!

Thanks all