Please verify that the component did install into the Assembly cache %SystemRoot%\assembly. It should show as:
Assembly Name - MultipleHash2005, Version 184.108.40.206, Public Key Token - 51c551904274ab44, Processor - MSIL
I expect that you will not find the file here based on the error message above.
Also verify that the DLL is installed in %ProgramFiles%\Microsoft SQL Server\90\DTS\PipelineComponents for 32 bit environments, and %ProgramFile(x86)%\Microsoft SQL Server\90\DTS\PipelineComponents for 64 bit environments.
I expect that you will find the file here because it was addable to the Toolbox.
(%SystemRoot% is probably C:\Windows and %ProgramFiles% is probably C:\Program Files)
If the DLL is not in the Assembly (most probable given the error), then the install into your .Net assembly failed. You can Drag the file into the assembly folder from the %ProgramFiles%\Microsoft SQL Server\90\DTS\PipelineComponents folder, and this
should correct the problem. Or you can use the gacutil command:
gacutil -i MultipleHash2005.dll