Nevermind. Somehow the source tree required a complete wipe and fresh checkout to get it right. It works now.
This might give you a false sense of security. The dumping process dumps the modules in an order based on how the directories are listed by the filesystem. If there is a bug which causes dumping to fail if the modules are dumped in a particular order, then wiping the tree and doing a fresh checkout may change the order in which the modules are listed, simply hiding the issue for the time being. Then it pops up later, typically on someones build slave in pikefarm where you can't easily debug it. It has happened before, it will happen again...
I think we should fix this somehow, but can't quite decide on whether the best solution would be to make the order less random, or _more_ random...