I have seen it mentioned in the comments of an unrelated issue (#1202), but I wanted this problem to have its own issue - the game crashes when elder prismarine is enabled (with stairs and slabs enabled) and marble disabled. Tested on r1.5-147 with ARL 1.3-27 and Forge 14.23.5.2836. Crashlog. Caused by the elder prismarine stairs ctor referencing marble. Perhaps registration of blocks and items shouldn't be configurable.

For the record; I also had marble disabled when I had the same issue.