Time to update this item… Adobe has released a 64 bit version of their iFilter: (the file date in the download is 11/26/08)
• Microsoft Windows Server® 2003 x64 Edition R2 with Service Pack 2: SharePoint Server 2007, Exchange Server 2007, Windows Desktop Search 3
• Microsoft Windows Server 2008 x64 with Service Pack 1: SharePoint Server 2007, SQL Server 2005, Windows Search 4
If you are running the 64 bit version of MOSS Indexing then you need the 64 bit versions of your iFilters, or the Adobe 32 bit workaround. You still may want to consider the FoxIt 64 bit PDF iFilter. Do a some blog searches and see what people are saying about features and performance. The FoxIt version sounds pretty good!