Endnote tools not showing in Word 2008
Try going through the instructions on the Endnote websitehttp://www.endnote.com/support/faqs/CWYW/faq1.asp#macENX1WORD2008 - note especially the SP1 (12.1.x) update for Word.
Endnote tools not showing in Word 2004
Try going through the instructions on the Endnote website.
Citations not importing from Safari
Safari only seems to download citation files to the desktop; they then need to be click-and-dragged into Endnote. Instructions here suggest a fix but I haven't been able to investigate yet - it might only be a partial fix. If you can bring yourself to use Firefox, it works a lot more smoothly.
Citations not importing from Firefox
The first time you export citations from a database it asks you whether to open or save. Choose "Open", then browse to find Endnote X2, and make sure to click "Do this every time" before clicking "Okay".