HOTFIX: IE6 and IE7 may not find the text even though the Web page contains the text
This problem occurs because the maximum number of paragraphs that Internet Explorer can search is 32,000 paragraphs. Internet Explorer may not find the text if the text is located after the maximum number of paragraphs.
http://support.microsoft.com/default.aspx/kb/936955
A comprehensive list of IE7 related Knowledge Base articles can be found here:
http://www.ie-vista.com/kbase3.html