How about yet another way:

* timer method

do case
case thisform.copyFilesNow
  * copy files
    thisform.copyFilesNow = .f.
otherwise
  =adir()
  * check if the files are there
  if <<the files are there>>
    thisform.copyFilesNow = .t. 
  else
    thisform.copyFilesNow = .f.
  endif
endcase

* you need to add copyFilesNow property to your form