Apple released a statement warning users upgrading from Leopard, about the newest available upgrade for Mac OSX to 10.5.6. The problem occurs from an incomplete software update getting into the update process that can cause Mac OSX to cause errors during the "Configuring Installation" window process.
Apple recommends users, if they haven't already, to force the software update process to quit the download, remove the partial update from your library and re-download the update. This problem is also been found in the standalone update from Apple's web site, and the combo update.
If users still faced with problems updating their Mac OSX machine, they are encouraged to contact Apple with related issues.