Certainly, unusual as with SQL Server 2005 developer edition SQL FTS is installed by default. I don't have an X64 box to test this on, but can you create and query a FT Catalog? If so, could you run the following SQL quieres on your x64 problem machine and post the results?
select * from sys.fulltext_index_columns
select * from sys.fulltext_catalogs
Regards,
John
SQL Full Text Search Blog
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John T. Kane