0.1.4 incompatibility

[robpark]

I'm using ember-cli, but still on an older version. 0.1.3 of ember-idx-tabs is working fine for me, but 0.1.4 won't build with the following error. This also happens on a clean project for me, so perhaps it's a 0.1.15 :: 0.1.4 incompatibility?

version: 0.1.15
Livereload server on port 35729
Serving on http://0.0.0.0:4200/
Invalid tree found. You must supply a path or an object with a `read` function.
Error: Invalid tree found. You must supply a path or an object with a `read` function.
    at readAndReturnNodeFor (/Users/rob/dev/eyenetra/portal/node_modules/ember-cli/node_modules/broccoli/lib/builder.js:71:13)
    at /Users/rob/dev/eyenetra/portal/node_modules/ember-cli/node_modules/broccoli/lib/builder.js:92:24
    at $$$internal$$tryCatch (/Users/rob/dev/eyenetra/portal/node_modules/ember-cli/node_modules/rsvp/dist/rsvp.js:490:16)
    at $$$internal$$invokeCallback (/Users/rob/dev/eyenetra/portal/node_modules/ember-cli/node_modules/rsvp/dist/rsvp.js:502:17)
    at /Users/rob/dev/eyenetra/portal/node_modules/ember-cli/node_modules/rsvp/dist/rsvp.js:1096:13
    at $$rsvp$asap$$flush (/Users/rob/dev/eyenetra/portal/node_modules/ember-cli/node_modules/rsvp/dist/rsvp.js:1581:9)
    at doNTCallback0 (node.js:408:9)
    at process._tickCallback (node.js:337:13)
^CCleanup error.
tree.cleanup is not a function
TypeError: tree.cleanup is not a function
    at cleanupTree (/Users/rob/dev/eyenetra/portal/node_modules/ember-cli/node_modules/broccoli/lib/builder.js:128:19)
    at /Users/rob/dev/eyenetra/portal/node_modules/ember-cli/node_modules/promise-map-series/index.js:11:14
    at $$$internal$$tryCatch (/Users/rob/dev/eyenetra/portal/node_modules/ember-cli/node_modules/rsvp/dist/rsvp.js:490:16)
    at $$$internal$$invokeCallback (/Users/rob/dev/eyenetra/portal/node_modules/ember-cli/node_modules/rsvp/dist/rsvp.js:502:17)
    at $$$internal$$publish (/Users/rob/dev/eyenetra/portal/node_modules/ember-cli/node_modules/rsvp/dist/rsvp.js:473:11)
    at $$rsvp$asap$$flush (/Users/rob/dev/eyenetra/portal/node_modules/ember-cli/node_modules/rsvp/dist/rsvp.js:1581:9)
    at doNTCallback0 (node.js:408:9)
    at process._tickCallback (node.js:337:13)