Recently I was building a BDC application using the “Business Data Catalog Definition Editor”. It’s a nice free tool that comes with the MOSS SDK, By default it generates the SpecificFinder and IdEnumerator methods.It doesn’t do the same for the Finder method. I was trying to create one Finder method and landed up in the following error that says “Could not find exactly 1 Member with name ‘[ColumnName]‘ Parameter name: fieldname”, before figuring out it is not my mistake I spent couple of hours to make sure that all the steps I have followed is right . Finally I came across this article that helped me to solve the issue {Thanks Chris}. As it was hard to find the solution in the net I am reposting the steps to resolve the error.

Key point here is that In Parameters should be specified before the Return parameter. That will solve the issue.