The Tips in detail

 "Compound-objects don't work."

This is a problem most prominent with versions prior to 3DSM3.x.

Basically: They do work. But: The more complex the subobjects are, the more likely it is that the result is not what you might expect.

As a workaround you should try to make the bolean object in a different scene. Although it seems to be true that the higher the number of faces per object is, the more likely a false or unexpected result is.

Sometimes adding an "optimze mesh" modifier helps. Sometimes the vertex-count plays a key-role. In other cases if A-B doesn't do it, try B-A.

Also a collapsed modifier-stack can help, too (this has other cons to keep in mind). Always try boolean ops on copies first before you do "it" to the real thing. Use a different file while experiencing the boolean ops. Also refer to: "Compound Objects disappear"