This post is more than 2 years old.
For a long time I haven't been able to get the RDS extensions (available with Flex Builder) to work on my Mac and Eclipse 3.2. To be clear - the RDS database stuff worked fine. But RDS file view would not let me edit files. With the recent release of Flex Builder 2.1, I grabbed the ColdFusion Extensions and decided to try again. This time it worked great.
For those who have no interest in Flex Builder 2 but do want the ColdFusion Extensions, you can right click on the Flex Builder 2 installer and extract it with WinZip. Or you could just install Flex Builder 2!