How to close a sheet

I have a script for Transmit and it works fine except after the synchronization is done there is a sheet or whatever you call it comes down with a message and an “OK” button. You have to hit “OK” to proceed. This means my script gets an error when it tries to quit Transmit. Can anyone help me find out what to do in the script to say “OK”?

-- Transmit AppleScript Synchronization Example 
-- Wade Cosgrove 
-- Shows how to AppleScript a simple synchronization 

tell application "Transmit" 
    -- Create a new session window for the script 
    make new document at before front document 
    -- send commands to the frontmost document window 
    tell document 1 
        if (connect to "" as user "" with password "") then 
            --Set your stuff listing to "Sites" folder 
            if (set your stuff to "/Users/Desktop/xml") then 
                if (set their stuff to "/htdocs/www/xml") then 
                        Begin synchronizing modified remote files with local files 
                        Can specify the direction and method Transmit uses for synchronizing. 
                        Direction can be: upload files / download files 
                        Method can be: update / mirror 
                    synchronize direction download files method update with time offset 0 
                    display dialog ("An error occured, could not change remote folder to www") 
                end if 
                display dialog ("An error occured, could not change local folder to Sites") 
            end if 
        end if 
    end tell 
end tell 
tell application "Transmit" 
    quit saving "no" 
end tell