You're probably getting a wifi hiccup and it's stopping the download and can't continue. Downloading large files on a phone is never a good idea - however there are download managers for free for Android on the google app store that I've seen. Probably your best bet.
In the end if you can - use a PC. I hope you're not going to emulate it on a phone, even with the best chances are it will run slow as snail, have multiple graphical errors or just plain not work. Beware of "fake" PS2 emulators for phones too!
