Ok here's how to change the attribute colours:
1. Edit (or download someone else's) fm colours.xml in Program Files\Sports Interactive\Football Manager 2006\data\settings
2. Uncheck Use Skin Cache in options/preferences in game.
3. Change the skin (to any other skin than the one you're using), then Confirm.
4. Change the skin back to the one you want to use.
5. Re-check the Use Skin Cache box.
6. Your attributes should now show the changes.
You can download attribute colours here:
attribute colours
The readme is in italian, but just follow the instructions above.
Hope this helps