http://www.staredit.net/index.php?showtopic=33493That was my original problem. A slightly older version of Memgraft was messing up the "Burrow" command.
Now it's messing up add-ons. I have exhaustively checked all requirements, and they are either the defaults or what I changed them to. These changes worked fine until I got the newer version. Now, I press the button, it asks me where to build the building, and then doesn't do anything when I tell it where. Preplaced add-ons work fine, but I can't make them in-game. What's up with Memgraft?
Also, I think I'm going to downgrade to 1.12b (instead of 1.13e) so I can make something in the Zerg tech tree work the way I want it to. Where can I find Memgraft 12b? And does it have these issues?