how do i upload a crossdomain.xml to the root of my webserver??

i’m new to this…. but i’m trying to install a cooliris wall on my blog and it gave me some script to make an xml file.

i’ve made the .xml file, but the trouble is that i don’t know how to upload it to the root of my webserver.

you can see the error on my website here…
http://inadvertentarchitecture.com/about

(extra help if possible… anybody know how to get the cooliris wall to show up on the home page http://inadvertentarchitecture.com -not- http://inadvertentarchitecture.com/about)