Demo upload Error

Hello
I am sorry for asking the similar question. But i am new to wordpress so therefore asking. During Demo Content import at step 3 after clicking on submit according to the documentation. The browser started loading then after a while it stopped. So i reloaded it, maybe i shouldn’t have. And there was a warning saying that the information will be resend. I did it. Then it started loading and stopped at a blank page.
Then i pressed back. The following error was given on the screen :

http://i.imgur.com/7phnB1X.png

Note : This error came when i pressed back button because after submitting import the screen starts loading then stopped and was blank white nothing showing.

Something i would like to note. In your doc about deleting demo imported files from \wp-content\uploads. Sorry for the silly question but where is \wp-content\uploads . I mean i haven’t download anything from wordpress. I basically bought hosting service from godaddy then installed wordpress there and it took me to the wordpress admin panel and i uploaded the theme. Is there someway to delete the demo without downloading anything. I mean like from the website admin dashboard. Or do i have to download something from wordpress to solve these problems. As i noticed you told in the doc to change max execution time in php.in file. But i am using wordpress from website. I am abit confused. Please help me.

By the way, some of the images seem to have uploaded in my site. But there is no menu or anything.

If you would like to see the site to understand the problem then i can give you a link.