Symantec DLP does not support RHEL x64 on version 10 and under.
To make packetcapture work you will need to reinstall the OS with 32 bit Linux / RHEL then reinstall Symantec DLP and configure as Network Monitor.
To find out if you are running 32 bit or 64 bit RHEL you can run the following command: uname -a
If you see x86_64 then you are running a unsupported OS
If you see i386 then you are running a supported OS and have a different problem which you may need to contact support for and provide your packetcapture and filereader logs.
Supported output: [[email protected] ~]# uname -a
Linux lakota.engdlp.symantec.com 2.6.18-92.el5PAE #1 SMP Tue Apr 29 13:31:02 EDT 2008 i686 i686 i386 GNU/Linux