Search Issues in Acrobat 8 Professional

Hi
 
Sub : Search Issues in Acrobat 8 Professional
 
We are currently evaluating Acrobat 8 Professional using a trial copy downloaded from the Internet. We have created a PDF which has about 2000 pages. When we try to search through this file, we find that it is not returning search results beyond the first 100-150 pages.
 
Is this a known issue or do we need to do anything here?
 
Any help would be appreciated.
 
Thanks
Ramesh