Not really an issue, I just dont know how to post a question.
Click the FM Pro Forum tab at top of this screen (and if you are reading this as email, you must return to the forum to respond...)
Then click new forum post on the right. That posts your question were such "How to use" questions are expected.
To answer you question, no script is required to do this.
On the field where you want the fill color to change, assign a series of conditional formats--one for each color option listed as a radio button in your field.
Say you have two radio buttons for "Red" and "Blue".
You might create two conditional formats for a selected field or group of fields like this:
yourtable::radioButtonField = "Red"
yourTable::RadioButtonField = "Blue"
For the first expression, specify a Red fill color. For the second, specify blue.
To add more colors, just add more expressions matching a value from the radio button field to a fill color.