Hey I don't know if this helps but try using the the name of the sheet in ''. It worked for me. I found your question in another forum as well
Also this guys looked like he knows what he was on about --> (
http://www.google.com/support/forum/p/Google+Docs/thread?tid=1c1a648f0494cf1f&hl=en)
webpage
Goodluck!!
My first post ever!! o.O