Hi Dee,
'Lion' and 'Swim' were placeholder error messages that I never got round to fleshing out.
The good news is that I've updated the error messages now, and they should also point to a line number.
'Lion' was an error message that should have informed you that the block_when (or block_when_not) conditions have to reference a regular boolean (that you can set true and false) rather than a dynamic boolean. This is down to the 8-bit game engine not supporting them. It should be easy to avoid using dynamic booleans in this context.
'Swim' is a little interesting because I don't see anything in your code that should trigger it. I've rewritten the message as this now.
Block condition invalid, supported conditions are:
'block_when', 'block_when_not', 'block_when_carried',
'block_when_not_carried', 'block_when_not_exists',
'block_when_exists', 'block_when_worn', &
'block_when_not_worn'.
but, as I say, in your included code, I don't see you not using one of those conditions.
When you see the (above) message, look at the line number of the error, and send me the block code that is failing (you can switch out any specific text that is secret of course).
Let me know how you get along.