What is the version of Illustrator that you are trying to download and from where and on which operating system?
What is the error message that you get? An error screenshot would help.
It seems you have slow internet connection. Reboot the machine and then try downloading the same from http://www.adobe.com/products/illustrator.html and check.
Ím trying with Cs6 just from the adobe website http://http://www.adobe.com/cfusion/tdrc/index.cfm?product=illustrator&loc=he_il .
It says an error occures during the download, nothing else i think. If it happens again i will screenshot it and post it. My internet should be fine, havent had any troubles with it in the past?