What could be causing this PDF error - version `GLIBC_2.4' not found on my 64 bit system?

[rsimmons]

2010-11-17 16:11:34,210 DEBUG FF stderr: LoadPlugin: failed to initialize shared library /apps/splunk/etc/apps/pdfserver/bin/firefox-x86_64/plugins/libflashplayer.so [/lib64/tls/libc.so.6: version `GLIBC_2.4' not found (required by /apps/splunk/etc/apps/pdfserver/bin/firefox-x86_64/plugins/libflashplayer.so)]

[rsimmons]

The error message version `GLIBC_2.4' indicates a version issue.

You can use the command ls -l /lib64/tls/libc.so.6 to verify that you have the correct lib version.

On 64 bit systems glibc 2.4 is required for 64 bit systems, eg. Centos 5.0 or later)