Actually, indentation of outline-numbered lists is problematic in several
Word versions. You may have been lucky before.
Note that the general idea of an outline-numbered list in Word 2007 remains
the same, that is, it should be style-based. It is recommended that you set
up your outline (multilevel) list as a list style: On the Home tab, click
Multilevel List, and then click Define New List Style. Type a name for your
list style. To set up number or bullet formatting, indentation, etc., click
the Format button, and then click Numbering. You will see a dialog box
similar to that of previous versions (and you may still find certain aspects
of the article at
http://www.shaunakelly.com/word/numbering/OutlineNumbering.html useful). The
dialog box also allows you to associate a paragraph style with each level;
in fact, this is also recommended.
To apply numbering or bullet formatting to text, you can apply the list
style (for example via the Apply Styles pane), but assuming that you defined
a paragraph style for each level it would be easier to directly apply the
relevant paragraph styles.
Whenever you need to modify a list style, right-click its icon under Home
tab | Multilevel List (look under the "List Styles" heading). Alternatively,
use the Manage Styles dialog (to display it, first click Ctrl+Alt+Shift+S;
in the Styles pane, click the Manage Styles button).