You probably do have entries within your windows registry that bind this "Fusion One" software to your Outlook 2000 each and everytime it starts.
You have 2 basic options, either remove your "fusion one" software from this computer, or perform a re-install of this software if it is important for you to use with Outlook 2000.
That referenced DLL file is either outright missing, corrupted or has been moved.
If you regular Add/Remove programs option does not work, you may have to seek out manual removal methods (This is if you choose to get rid of "Fusion One" software) which I know you can find in your avail programs.
Paul