I have built rdfDB on linux and bsd. If you port it to other systems, drop me a line or better yet provide me a link to a binary that I can post here.
The sources are available under the Mozilla Public License. Sleepycat's software is GPLed. I plan to have a version of rdfDB that does not depend on Sleepycat.
You can get the x86 Redhat 5.2 linux binary from here.
The perl DBI driver for rdfdb can be obtained from here. You need to have the perl DBI module to access rdfdb from perl.
The most recent version number is 0.46