Gack, how did I miss this! Sorry!

My Daphne used to love kicking out the litter, she's gotten better about it with age and also after we switched to Carefresh litter. You can also try a litter box with a hood on it, like for a cat. Spaying and neutering also do wonders for litter troubles and longevity. Here's a link to more great litter training tips and tons of other helpful stuff. Chances are they just don't like that particular sort of litter. Rabbits are funny like that.

http://www.rabbit.org/faq/sections/litter.html

And incedentally... Holland lops are adorable. When we get our next rabbit, we're planning on a Holland or mini lop.