I retried the original link just now but from a different machine running Linux. Clicking on the "Download Now" button started the file download but also opened another popup window. This time the popup played music and tried to sell me some sort of video. Opening with Firefox on the same machine gets me a popup for something called "Force of Empire" from a gaming company. Another attempt on Chrome gets me a popup from "GameNinja".
So it appears the site forces a popup advert for each download - I just got unlucky earlier today that the popup was for a well known trojan malware download. Yes - I could block ads but many of the web sites I frequent depend on ad money to survive so I don't.UPDATE :
However, there is a link on the CHDK Wiki Software
page that points here :https://docs.google.com/folder/d/0B08pqRtyrObjSmFqSV8yRUlqbnM/edit
If click that and you scroll down, you will see a file called Auto CHDK to EXIF v1.4-complete.zip
which, unlike the link posted above, contains source code and a readme file. Might be a better place to obtain the program.