WebSphere Update Installer

I try to put an update on, (update 000015) for WAS61, and get the following:

Prerequisite checking has failed. Failure messages follow:

A general exception has occurred during prerequisite checking. Check the log files for more information.

Thanks IBM - maybe you could tell me which log files?

Eventually found them in "D:\IBM\WebSphere61\UpdateInstaller\logs\tmp1"

CWUPI0026E: was the main error.

I googled this and they said I need to use a newer installer...