Thanks for your quick reply, TIG!
I downgraded Lion on my macbook to Snow Leopard and everything seems fine.

Hi everyone

As you can see, all the slots in the Inspector are always black.
I reinstalled Sketchup and SP as well several times but it's the same.
I can see figures when they're highlighted so it's no big deal.
The real problem is that the number I type in won't be saved and it keeps going back to the default '0.0' every time I click on something else.
It's so frustrating!

Could anyone let me know what causes this and how to fix it?

I use macbook pro, Os X Lion, Sketchup 8(free version), and the latest SP 3.2.

Thanks in advance!!!