"The installer encountered errors before iTunes could be configured."

I have been trying to download the latest version of iTunes for the past 4 hours. I keep getting this error up.

At the last moment it does a "rolling back action", and then says this message along with "Errors occured during installaion. Your system has not been modified".

Just to note, I downloaded iTunes before. But, I was encountering some errors (it detected my iPod, but it would not detect it through the USB cable in terms of now allowing me to Reset (under "version"). So I decided to uninstall, not realizing that now it wont ever install again.

Please help.