Not able to convert doc files in PDF by libreoffice in centos 5.2?

LibreOfficee virsion- 4.4.3.2
language - en
component - writer

I have install libreoffice4.4 in CentOS release 5.2 and use commends to try to convert Doc file in PDF use below commends but its create black pdf file. Please help hi to solve this issue.

/opt/libreoffice4.4/program/soffice --headless --convert-to pdf:writer_pdf_Export --outdir “/root/” “/root/test.docx”

or

libreoffice4.4 --headless --convert-to pdf --outdir /root/ /root/test.docx convert /root/test.docx → /root/test.pdf using writer_pdf_Export