Applescript filewrite

do shell script "/Users/Nick/Dropbox/Untitled.command"
set theFile to "/Users/Nick/Documents/values.txt"
open for access theFile
set fileContents to (read theFile)
close access theFile

set costItems to {}
set x to 1
tell application "System Events"
    set XMLRoot to make new XML data with data fileContents
    repeat with searchItems in (XML elements of XML element "searchResult" of XML element "findItemsAdvancedResponse" of XMLRoot)
        set end of costItems to value of XML element "convertedCurrentPrice" of XML element "sellingStatus" of searchItems
        if x is not 5 then
            set x to x + 1
        else
            exit repeat
        end if
    end repeat
end tell
return costItems

tell application "Finder"
    try
        set the_file to "/Users/Nick/Documents/outputvals.txt" as POSIX file as alias
    on error --file doesn't exist yet, so create it
        set the_file to (make new document file at ("/Users/Nick/Documents/" as POSIX file as alias) with properties {name:"outputvals", text:""})
        --Normally, when you're creating documents in this fashion, you would put the text you want in the document after the 'text' property, but for your sake I will use the alternative :)
    end try
end tell
set the_data to costItems
try
    open for access the_file with write permission
    write the_data to file the_file starting at eof
    close access the_file
on error --you never know when errors will crop up (when it comes to reading and writing files); better to be safe than sorry
    try
        close access the_file
    end try
end try