My issue was the same, but for a different reason. The update from the App store gave me the error 102. When I downloaded the update direct from the Apple site and tried to install that, I got an error that said my OS was incompatible with the update.
Here's how I successfully did the update:
1. Opened app store and went to the "updates" tab
2. At the bottom of the description for the 10.8.5 update is a tiny link that expands the package into components. Install each one individually by clicking on the "install" button next to each one. I was able to install all the components from this update using this method except iPhoto 9.4.3.
3. Search for "iPhoto 9.4.3 update" on the apple site (not the App Store), downloaded that and installed it.
This should work - if it doesn't, restart while holding down the "shift" key (puts you in 'safe mode') and try the above steps in safe mode.
Amber