Endnote tab does not appear when I open a Word document

I have Windows XP and EndNote X3.

I have followed the instructions on http://www.endnote.com/support/faqs/CWYW/faq45.asp and a dialogue box pops up stating  DllRegisterServer in EndNote Cwyw.dll suceeded.

However when I close all programs and reopen a Word document, the EndNote tab is still absent.

Any ideas?

What version of MS Word (or other) are you using?