I'm having trouble using Json Input step and get following error. I tried the sample transformation "JsonInput - read a file.ktr" which came along with PDI and get same error. Please advice.

Json input.0 - ERROR (version corp_pantheon_engine_pack-1.27.4, build 49066536 from Mon Jul 8 13:36:37 2013 (1373315797) by grapebot) :
Json input.0 - ERROR (version corp_pantheon_engine_pack-1.27.4, build 49066536 from Mon Jul 8 13:36:37 2013 (1373315797) by grapebot) : Error at engine init!Error :
Json input.0 - ERROR (version corp_pantheon_engine_pack-1.27.4, build 49066536 from Mon Jul 8 13:36:37 2013 (1373315797) by grapebot) : No script engine found for JavaScript
Json input.0 - ERROR (version corp_pantheon_engine_pack-1.27.4, build 49066536 from Mon Jul 8 13:36:37 2013 (1373315797) by grapebot) :
Json input.0 - ERROR (version corp_pantheon_engine_pack-1.27.4, build 49066536 from Mon Jul 8 13:36:37 2013 (1373315797) by grapebot) :
Json input.0 - ERROR (version corp_pantheon_engine_pack-1.27.4, build 49066536 from Mon Jul 8 13:36:37 2013 (1373315797) by grapebot) : No script engine found for JavaScript
Json input.0 - ERROR (version corp_pantheon_engine_pack-1.27.4, build 49066536 from Mon Jul 8 13:36:37 2013 (1373315797) by grapebot) : Error initializing step [Json input]

Ubuntu - 12.04LTS
PDI Build version : 4.4.0-stable
Build date : 2012-11-21 16.02.21