references in endnote x1 have become mixed up

the references in my word document have ‘skipped’ so that they are out of sync and are one behind. That is, where the reference should be against a statement, the reference for that statement is now against my next referenced statement. How did this happen, and how do I fix this? Thanks!

I would look first at this FAQ.

http://www.endnote.com/support/faqs/CWYW/faq22.asp