here are some important notes on the Unreal Tournament 2004 version of moviesandbox.
First of all, the download location of the most recent (and most probably final) package:
Please be sure to update your UT2004 installation to the latest version BEFORE installing Moviesandbox!
After downloading, just unzip the contents of the zip-archive to your UT2004 folder and use the MovieSandbox.bat file in the UT2004\Moviesandbox directory to start.
Alternatively, you can start UT2004 and activate Moviesandbox from the Community->UserMods Tab.
* It crashes on start and gives me a weird "not found" error message!
1. a simple reinstall (read: delete the moviesandbox folder and unzip it again) will do.
2. make sure you have updated UT2004 to the latest version. Make sure you install moviesandbox AFTER updating to the latest version.
Also, please have a look at the Bugs page on the wiki at:
Let me know if this works for you.