Building from a branch on an alt repo fails

[bookshelfdave]

erln8 --build --repo basho --tag=r16 --id r16b08p --config osx_llvm
Building r16b08p from tag/branch r16 of repo basho
Custom build config: --disable-hipe --enable-smp-support --enable-threads --enable-kernel-poll --enable-darwin-64bit
Custom build env:
Build log: /Users/dparfitt/.erln8.d/logs/build_r16b08p_2015-03-17T15:08:29.204975Z
[0] copy source                    fatal: Not a valid object name
[0] copy source
[1] otp_build
Here are the last 10 lines of the log file:
sh: ./otp_build: No such file or directory

[bookshelfdave]

This seems to move things along:

cd ~/.erln8.d/repos/basho
git checkout r16
git checkout maint