How to install and run GSC V 1.23 in Vista

You  must install and run the program as administrator.

Go to the folder where you installed it, right click the executable GSiteCrawler.exe and select Properties.

Go to the Compatibility tab and check the box near the bottom to Run as administrator.

Do the same thing for the program to compress the database DbCompress.exe. And the uninstaller Unwise.exe for good measure.

You will also face the typical Vista prompt "Are you sure you want to run ...".

For that in general there is a tweak you can apply from http://www.tweak-uac.com/  so it won't bother you every time you want to run a program.