Thank you for your post.
No color printing problems have been reported.
Since this worked for you under Windows XP, do you know if your printer driver is certified to work with Vista? We do not have a Xerox Phaser 6300 here to try, so any additional information you can supply may help others encountering the same difficulties.
I've had the same thing happen. At the time, (probably around the time of the initial post) I had the same thing happen using FMP ~(7 or 8) Advanced or whatever was out at the time, Windows XP Pro on an HP Compaq printing to a Xerox Phaser 6250. If I started a new solution from scratch (even importing everything from the "problem solution" it would print in color again) but I could never figure out what I had done just prior to losing the color. Today, I've had the same thing happen again. Using FMP11 Advanced on a Lenovo ThinkCentre but using the same Xerox Phaser 6250. Only this time, just prior to this, I had scripted some buttons to automatically print a couple of layouts. This time I tried deleting all the scripts that mentioned anything about printing but it did not restore the ability to print. Not quite sure how to proceed...I've had several years to think about. I should mention it only happened in one solution right now, but I am not going to touch any other one without making a backup first.