As a beginner I make notes in my notebooks on what I am learning as I go along, and I have also referenced the help files by pasting hyperlinks from them - this seems to break the Find function.
Is it really a bug (in V9), and if so is it likely to have any other effects?
To reproduce the issue, try this...
Create a blank notebook, enter some text including a keyword (e.g. MinValue) in a text cell. Select the keyword and press F1. Right click the target word in the help windw where it first appears in blue beneath the heading and select copy hyperlink. Paste the clipboard content at the beginning of the text cell, which now contains the pasted hyperlink (1st) and original typing 2nd.
Go to the beginning of the notebook, invoke Find, enter e.g. MinValue. Find next will find the pasted hyperlink. Pressing Find Next again will not move the found location.
Update - Bug Confirmation
WRI Case 652039: they confirmed by email 20/03/2014 that they had reproduced it and had passed it to development to fix, they hope to fix it in the next release.