Excel 2007 : Solver does not change values

I am trying to run solver to solve a Maximum Likelihood Estimation problem. It is a fairly complex function so I have a cell for the likelihood, which is a product of the elements of a column, which is the sum of other columns which are functions of the data and two parameters I am maximizing over. When I run the solver, (maximizing the likelihood cell, changing the two parameters) it says it finds a solution, but does not change anything when I choose keep solver solution. Any ideas about what could be going wrong?

I have attached the spreadsheet I am trying to do this on.

Thanks so much

My bad.
I am trying to maximize U102 by changing C2 and D2. I am not able to do it. I don't know how the solver got changed, but that was not the source of the problem I was having.

I think I solved it. I took the log of the column and maximized the sum of the logs instead of the product of the regular function. I still don't know what went wrong with the product way, but I now know how to solve the problem.