I think you're referring to what is a normal explorer window. The text color for explorer windows is set in the Classic Colors section - "Window/Text - Normal" in the right attribute pane.
If you are talking about the orange text itself, that reads "System Tasks", "Other Places" and "Details", in SkinStudio Explorer:
XP Shell/Task Pane/Panel Content/Title Bar
and
XP Shell/Task Pane/Special Pane Content/Special Title Bar
You'll see a "Colors" item in the Attribute pane on the right for each section. Nothing to clue you in that the colors referred to are text colors until you expand it, however. The text can have two color states: Normal (default) and Hover.
Hope one of those answers is what you're looking for.