Am I doing it right? I can't get codes for Emerald to work on my Gameshark SP

Hey guys
I recently bought a GameShark SP (U.S.) and Pokemon Emerald Version (U.S.) from Ebay. The plan was to use it together with my Gameboy Advance SP(EU). There were no codes which was previously programmed into my newly acquired Gameshark for Emerald version. So I had to find them myself.
So I had already found some Gameshark codes for Emerald version and I had also read some manuals and seen some tutorials for how to use a game shark. I read on ebay and saw tutorials on youtube.
I felt well prepared to test a few codes on the Gameshark, so I started typing the master code in which I found on supercheats forum.
But when I had typed it, I saw that the master code was followed by a series of zeros that are not included in the code as shown at supercheats.
I tried to delete them, but instead I deleted the whole line.
Finally I thought that it might just have to be that way, so I finished the master code with the needless zeros, and went ahead and started on another code.
I wanted to test the access PC code, but this was followed by zeros aswell.
I finished the code anyway, and started emerald. I tried to press select and b in game to access the PC as the code prescribed, but nothing happened. I gave up and tried another code, warp two Littleroot.
This code was not followed by zeros, so I hoped it worked. But despite the fact that I followed the procedure as written in Supercheats the code didn't work either.
Now I ask for your help. Can you tell me what I am doing wrong? Do I type the codes incorrectly? Does those zeros matter? Or is it not working because of a conflict between the EU GBA and the US game and Gameshark?
Hope you can help.