Before you start, please make sure you substitute the version number to the latest version should it be higher then what is used in the reference post below.

If you are running php4 or php5.1.6 you will need to get the cgi binary and follow the following steps:

Navigate to your cgi-bin directory. If you don’t know where your cgi-bin directory is, ask your hosting provider.

Then you should be set to install.

Please note: for the bootstrap installer, please use http://www.magentocommerce.com/downloads/assets/1.0.19870/magento-1.0.19870.tar.gz