220.127.116.11 - Great theme! Rated 5 out of 5 stars
Seems like I posted my previous comment too spontaneously.
I suddenly had a tiled background within my FF sidebar on my netbook, but not on my desktop machine.
Now, the theme is ok on both my desktop computer and my netbook (both of them running XP Home SP3).
After some examinations on the netbook, I found the localstore.rdf to be currupted for some unknown reasons.
Copying that file from the desktop machine to the netbook was the solution.
The second issue (two 'Close' buttons in the add-on install dialog) doesn't actually exist. I simply wasn't aware of the two different things those buttons are supposed to do.
I officially apologize for my wrong comment about this theme being broken.
Here are the five stars back again, now. :)