adding images

When trying to add an image to a page on my wordpress site I am reeciving this error message:

Add media files from your computer

Unable to create directory /home/cryztallized/www/wp-content/uploads/2010/09. Is its parent directory writable by the server?

I do not have a clue what this means or why it would be giving me this error. I have installed wordpress on other websites before and have never had this issue.

Any ideas?

Thanks