I am looking for maps for Heroes III.

GoedenDag, the link you provided leads to the main page of the website http://www.ex.ua/. It seems that quite a few days have passed since the file was uploaded and last downloaded, and it has been removed:

If an object has not been used for more than 30 days, it may be removed by the system.

To find the map on the Internet, it is best to know its exact name (the file name may not match it at all). A search query like "New Conquest of America map Heroes" (in both Russian and English) yields a huge number of links, but none of them are relevant.