此问题是由于xpdf 版本太低，导致预览报错。
下载 xpdf 3.04 版本 升级补丁 http://pan.baidu.com/s/1dD6P5iL
解压后覆盖到 /usr/xpdf 
linux-oracle-cwp:/home # pdfinfo pdf.pdf 
Title: <4D6963726F736F667420506F776572506F696E74202D20D6D0B9E3BACBB5E7D0C5BCCDD2AAA1B232303135A1B33130BAC5B8BDBCFE>
Author: P122342 
Creator: PScript5.dll Version 5.2.2 
Producer: Acrobat Distiller 9.0.0 (Windows) 
CreationDate: Thu Jul 16 10:33:25 2015 
ModDate: Thu Jul 16 10:33:39 2015 
Tagged: no 
Form: none 
Pages: 48 
Encrypted: yes (print:yes copy:no change:no addNotes:no) 
Page size: 595.22 x 842 pts (A4) (rotated 90 degrees) 
File size: 873330 bytes 
Optimized: yes 
PDF version: 1.6 
linux-oracle-cwp:/home # pdfinfo 
pdfinfo version 3.04 
Copyright 1996-2014 Glyph & Cog, LLC 
Usage: pdfinfo [options]  
-f : first page to convert 
-l : last page to convert 
-box : print the page bounding boxes 
-meta : print the document metadata (XML) 
-rawdates : print the undecoded date strings directly from the PDF file 
-enc : output text encoding name 
-opw : owner password (for encrypted files) 
-upw : user password (for encrypted files) 
-cfg : configuration file to use in place of .xpdfrc 
-v : print copyright and version info 
-h : print usage information 
-help : print usage information 
--help : print usage information 
-? : print usage information 
linux-oracle-cwp:/home #