Fireworks nav menu problem

I have made a navigation menu in PS and took it into Fireworks. I then started using the slice tool to chop up the different sections, add in rollovers and also added in a few pop down menus.

Now that was done, i wanted to resize the canvas…but its not lettings me. It fires up the following error:

“Could not complete your request. The selection was incorrect for this operation”.

[URL=“http://www.megaupload.com/?d=1W2PGFRT”]