When I sliced it with repG+skienforge, I needed to enlarge my java heap space (on linux, export _JAVA_OPTIONS="-Xmx1g") Do the same, or use a more advanced plater or slicer.

This is an interesting print because it gets harder the smaller it gets: in ABS, the pillars need to be of a certain size or they will bend too much during printing, and cool gets fairly important when using PLA.
Print both inside and outside stls and they should snap together and twist to lock.