Version 5.0b was build 160. If you don’t see a letter after the version number then you don’t have any of the updates. I recommend you download and install 5.0d. It includes several updates and bug fixes.
Similarly, if you have DVD Architect, the current version is 2.0b.
The reason for the 5.0b requirement is because that is when the grouping functionality was added to the scripting API. Grouping is used by a couple of the tools.