|According to Microsoft, Word 2003 is fully compatible with Windows 7, so is Office 2003 with SP3. (I assume you have the full Office 2003 Suite, not just Word?)|
Office 2003 has had three service packs in it's lifetime, the latest one being SP3 (obviously!). Has your Word 2003 been updated to SP3 on the Windows 7 PC?
I'm not saying that would fix the problem definitley, but it has to be considered.