IIS search not working

I have a page on my Intranet (using IIS6.0) that searches a directory of PDFs using the Adobe IFilter. It was working well until a few weeks ago, now nothing is found each time I search. If I run a query on the Index server, it finds everything, just my webpage is not working. The only thing I can think of that I might of done was install Service Pack 1 on my Windows 2003 server that is hosting the Intranet. Does anyone know if this could have caused the problem? if so, any idea how to fix it? Thanks