Have anyone tried this fluorescent dye, RiboGreen for RNA quantitation?
I use it with a normal fluorometer according to the kit's description but no reliable data has been generated yet. The fluorescent of the blank sometimes higher than the RNA standard or any of my samples.

Have you checked the integrity of the RNA? Run an agarose gel if you havent.

I've found out the problem, acctually. We wanted to order the Quant-iT RiboGreen RNA kit, but unfortunately, we ordered another kit with a similar name: Quant-iT RNA kit. I didn't know that is a different kit with a different type of dye, because searching for RNA dye on the Invitrogen website, that was the only appearance. And there was no manual sent with the kit. So we thought it was a RiboGreen kit! Now we have tw problems. This kit seems to be not as sensitive and accurate as the RiboGreen, and there are only a few reference in the literature. :(
Being honest I was not to use it for RNA quantitation but for cDNA measurement for qPCR assays.
One more problem: the RiboGreen costs almost ten times more than the other kit.
So I'm still full of doubts!