From the old FAQs: http://bigjohnd.org.uk/PM_FAQs/PM_FAQs.zip
Create a text box, select the text cursor and hit Ctrl+Alt+P
9.11 - Page Numbering 2
John Davies - 11:26am Jan 4, 2004 Pacific
When setting up page numbering Ctrl+Alt+P as indicated in the Helpfile does not work or loads up MS Publisher.
Instead of using Ctrl+Alt+P, use Alt+0024.
(To use Alt+0024, first ensure that Num Lock is on.Then hold down the Alt key and type 0024 on the number pad, under the Num Lock key.)
If Ctrl+Alt+P loads up MSPub, you will first need to find the shortcut to MSPub, either in the Start Menu or on the Desktop. Use your secondary mouse button to open the Properties of the shortcut, and then in the "Shortcut Key" field, delete Ctrl+Alt+P and enter None. Click OK.