You don't have to install the tar bundle - Openswan is in the CentOS 5.3 repositories:
From my 5.3 system:
Code:
yum list openswan
Loaded plugins: allowdowngrade, changelog, downloadonly, fastestmirror,
: priorities
Loading mirror speeds from cached hostfile
* base: mirror.5ninesolutions.com
* updates: ftp.lug.udel.edu
* addons: holmes.umflint.edu
* extras: mirror.skiplink.com
adobe-linux-i386 | 951 B 00:00
base | 2.1 kB 00:00
updates | 1.9 kB 00:00
addons | 951 B 00:00
extras | 2.1 kB 00:00
Available Packages
openswan.i386 2.6.21-5.el5_4.2 base
If you remove what you installed then run "yum install openswan" you will get the prebuilt package for CentOS 5.3 which is your distro. (The 2.6 stuff is your kernel version not your distro.)