There is no version of BD Rebuilder that isn't designated as Beta. The early versions had a forced expiration date, but any version newer than 0.49.07, which was released in November of 2014, does not expire. You can continue to use the newer versions as long as you wish.
Stick to the current version unless you have a specific problem with it. And if you do, file a bug report over at the Doom9 forum thread meant for those reports: http://forum.doom9.org/showthread.php?t=143716 You should read the information on that first page anyway, to help set up the program.
To convert a Blu-ray to DVD-video, you would need to select Alternate Movie Only Output, remove the check mark from the box next to Output BD or AVCHD structure in the little window that pops up, then select either DVD-5 or DVD-9, depending on what size DVD you want. If you live in a country that uses PAL standards for DVD, you should also go to Settings-->Setup, and change to PAL output for DVD.
If you want Blu-ray structure, or AVCHD on a DVD disc, just change the Output options Target size.