"Character File does not exist."
Attempting to open a performance in Retargeter without having selected a valid character setup xml file.
In the Open Performance dialog, make sure that you have a valid .xml file selected in the "Character Setup File" field before pressing OK.
For more information about opening a performance in Retargeter, see the following article: Retargeter Pro Workflow
For more information about Character Setup in Retargeter, see the following article: Character Setup