Sims Install Issue

Hello,
     This is not my first time downloading the sims 3( and all expansions, but the problem is with the initial sims 3 base game). so i downloaded it from www.games4theworld.org, used Utorrent to download it. It was 5.04GB for the game. When finished, i opened with Winrar 4.20 also downloaded from www.games4theworld.org. I extracted to a folder on my desktop. I mounted both images using Daemon tools lite. I get about half way and select the other disk( i know this is normal). Then when it gets to about 90% it asks for another disk that has Fullbuild1 on it, also at the same time, the image (the one with fullbuil1 on it) unmounts, which causes this error...t\i could switch disks all day and it would still not complete...what is different since the last time i did this( less than 3 months ago). Please keep in mind, i have done this 100x...thanks!