Indexing Service (MSIDXS OLEDB Provider) Error - Impersonation Fai

[YK]

I'm using the MSIDXS OLEDB provider in my ASP.NET application to search/query
the Indexing Service catalogs for information. This works fine on my server
until I upgrade my server with patches. After I installed the patches, and
..NET Framework 1.1 with SP1, the application throws exception "HttpException
(0x8004005): Impersonation failure" when my application query the Indexing
Catalogs.

Previous Configuration (everything works):
- Windows 2000 Server SP2/IIS 5.0
- .NET Framework 1.0 with SP2

Current Configuration (MSIDXS OLEDB fails):
- Windows 2000 Server SP4/IIS 5.0 with latest patches
- .NET Framework 1.1 with SP1

Please help.

Thanks,
YK