1. Download and install Adobe Extension Manager CS3 1.8+ if you haven’t install it. You can download the newest version here: Download Adobe Extension Manager CS3.
2. Unzip the downloaded file (productname_v_x_x_x.zip).
3. Start Adobe Extension Manager CS3, from Start > All Program > Adobe Extension Manager CS3.
4. In Adobe Extension Manager CS3, go to menu File > Install Extension
5. In the file browser dialog box, navigate to the directory where you unzip your files.
6. Select ProductName.mxp and press OK. Installation will start.
7. Install finished. You can find the installed product in the Components Panel of you Flash CS3.