Hi,
What is your Invigorator version? I am asking because you don’t need to save to ai version 8 since a long time ago.
Make sure that you add a stroke and/or a fill to your artwork. If it has none It won’t work in Invigorator and you will get the “No usuable Vector Paths in this file” warning.
For text Steve answered your question.
Salut.
Serge