main checksum generator, how to use it ???

Hey all, i was following this tutorial
http://forum.ragezone.com/f197/main-...erator-422560/

to generate new checksum.dat....
sorry for my question, but...how to do it ???
i've downloader the cmainchecksum generator but when i click on it appear
"internal error occurred".


Sorry, im so noob xD , but how it works ???
http://i49.tinypic.com/2qdwxli.jpg

this happen even if i put main.exe into this folder...

Right click and "Run as Administrator" and see if that helps out.