By the way, newish versions of org actually report back any error message from the babel block. In this case, org tells me:
Error: /tmp/babel-4890lUw/dot-48901c0: syntax error in line 3 near '[' i.e. the first node line. -- : Eric S Fraga (0xFFFCF67D), Emacs 25.0.92.1, Org release_8.3.4-739-g789412
