I have recently bought your book, Python For Kids and I think it's great and easy to understand except for one small thing.

It tells me to put this into the Shell:

spaces = ' ' * 25
print('%s 12 Butts wynd' % spaces)
print('%s Twinklebottom heath') % spaces)
print()
print()
print('Dear Sir')
(excerpted)

I do what it says, I click run module, but I get this error:
error in editor window
I'm new to this, so I probably made some extremely stupid mistake, and i'm sorry if this is the wrong place to ask.

When I enter your code, I get the same error. But once I click OK, in the editor window I see the following:
error in editor window
That red highlight, on the third line down, shows you on where the error has occurred - and hopefully gives an idea about what might have gone wrong. In this case, Python isn't expecting a bracket at the end, because you've got one earlier in the line: print('%s Twinklebottom heath') % spaces). If you remove that bracket -- it should look like this print('%s Twinklebottom heath' % spaces) -- you'll find the program runs as expected.