Some problems

To whom it may  concern:

   I have met the following problems. Pls help to find out the reason:

   1)I have asked you to send me a program in http://www.longbowdigitalarts.com/dxb2game12.exe. The server split it into 11pcs & sent 11 mails to me. As I saved to my computer & run the 1st program, it didn't work,& appear that "(CRC)parameter mistake", Why? Which tool the server uses to cut files? How can these split files be united?

   2)I have asked the server to send http://139.175.250.171/shooting/gun-se.zip to me. As usual, the server sent me 7 split zip files. But as I tried to extract these files, it also didn't work & showed "bad zip file". Why?

   Looking forwards to hearing from you! Many thanks!