I've been using WB 4.6 and Outlook 2003 without any problems whatsoever. But I don't use MS Word 2003 as my e-mail editor. Have you checked in Options to see if this option is checked/unchecked?
Turn Word on or off as your default e-mail editor for all new messages:
1. From the main Microsoft Outlook window, click the Tools menu, click Options, and then click the Mail Format tab.
2. Select or clear the Use Microsoft Word to edit e-mail messages check box.
