Sources that have a mini-display port or a display port, or DVI-I output connection can all have the same problem - a good signal on a digital connection like HDMI, and a purple or pinkish image when utilizing an analog VGA cable.
This is an issue with any device that can support both digital and analog video out. When the source first connects to the SVSi encoder, the source and encoder exchange EDID information. The EDID on the SVSi encoder lets the source know that the encoder supports both digital and analog video. The source will then output digital video (since it is preferable). Since the cable between the two units is analog, this will cause the color change.
The resolution to this issue is by doing one of the following:
1) Making sure any device that can support both analog and digital output is connected via a digital connection
2) Add a secondary SVSi encoder, with the EDID set to force analog only (a drop down option in Encoders running the latest firmware). This will tell the source the encoder only supports analog video (and two channel audio) and help force the source to output the correct video type.