Actually it does start download and after few hours (for 1 file ~ 140MB) it interrupts and file downloaded is useless.
There is no CocoStudio v3.0 or v2.2.3, that is the Cocos2d-x release version.
If you means the CocoStudio v1.3 (Latest version now), try this site to download.
I can't be the only one suffering this problem as well. I'm currently on my sixth attempt to download this. Resuming seems to start at the beginning again. A torrent would be a good idea here.