Division of two columns across multiple rows

Hi-
I've been trying to modify the code found here: http://www.excelforum.com/excel-prog...other-set.html but can't seem to figure it out, and as a lot of people have said, I'm new to macros. I need to take column E and divide it by column C for each row. The final product would look like this in long hand:
=(1/69)*((E4/C4)+(E5/C5)+(E6/C6)+(E7/C7).... (E72/C72))*100.
In the attached spreadsheet, the macro would be working on "By prey item" sheet, but the result needs to go on "Fish Techniques Results" in the percent by weight column. This will need to get rerun for each prey item (Diptera, Amphipoda etc) and for both percent by weight and numbers (column E for Diptera in By Prey Item and going in Column C on Fish Techniques). Hope that all makes sense.

Also, does anyone have any suggestions for a good text book to get deeper into Macros? I have not perused the forum extensively for this answer.

Thanks for your help.

ReDim
In plain English means "Resize" of the array.
If you have look at the code, I have commented cells(In green). The output could have written directly in to range(sheet), instead of first copying in to the resize array(Z). If you uncommented these two green lines, when the code finishes each row, the result will be copied one at a time, but with redim statement, the code writes back in to the range once it finishes lopping through the rows. The advantage of the redim is to speed the execution of the code, which may be the factor if you have large data.

Merged cells and VBA are not good friends.
When you merge cells, two cells are merged in to one. And when a code loops through the merged cells, it will not find which of the cells the code is referring to. It is highly likely you will get an error, or unexpected result. So avoid, merging cells