Thank you all for the wonderful script!
I extended the script: You can select a folder in the file-editor. The structure is examined recursively: In this folder and in all sub-folders all ".pages"-documents are taken and converted to word-documents. It might help some people:
tell application "Finder"
set theFolder to choose folder
set theList to entire contents of theFolder as alias list
repeat with thisItem in theList
set nameItem to name of thisItem
set kindItem to kind of thisItem
-- if it is a folder, kindItem is "Folder".
-- if it is a pages document, kindItem is "Pages Publication".
if kind of thisItem is "Pages Publication" then -- only pages documents are considered
-- here the pages-documents are converted to a word-document
tell application "Pages"
open thisItem -- The file is opened in pages
set docName to name of front document
-- Remove .pages extension
set prevTIDs to AppleScript's text item delimiters
set AppleScript's text item delimiters to ".pages"
-- Add .doc extension.
set docName to first text item of docName & ".doc"
set AppleScript's text item delimiters to prevTIDs
-- Get folder of the file
tell application "Finder"
set sourceFolder to (container of thisItem) as Unicode text
-- display dialog sourceFolder
end tell -- Finder
-- Save file to the same folder
set docPathAndName to sourceFolder & docName
save front document as "Microsoft Word 97 - 2004 document" in docPathAndName
close front document
end tell
end if
end repeat
end tell