Yuglify compressor error with django-pipeline

I am using yuglify css compressor to compress css with my django-pipeline .

I have installed required packages, gems and npm packages, then precompiled the assets.

but when running python manage.py collectstatic

its saying Compressor Error:Killed

What should I do to get rid of this.

I am listing out my packages and gems with version below.

node v0.10.32
npm v1.4.28

npm packages:
yuglify 0.1.4
bower 1.3.8

djang0=1.5.5
django-pipeline==1.3.19

gems:
ruby 1.9.3
bootstrap-sass (2.3.2.2)
compass (0.12.2)
dotenv (0.9.0)