diff -rupN filefield/filefield.js filefield_new/filefield.js
--- filefield/filefield.js	2009-07-04 07:22:57.000000000 +1000
+++ filefield.js	2010-02-10 20:13:55.000000000 +1100
@@ -130,3 +130,37 @@ Drupal.filefield = {
     return false;
   }
 };
+
+/**
+ * This disables the submit, preview & add-more buttons while a file upload is in progress.
+ */
+
+// Disable buttons
+Drupal.behaviors.waitSave = function (context) {
+  $('.filefield-element .form-file', context).each(function () {
+    $(this).change(function() {
+      if($(this).val() != '') {
+        $('#edit-field-file-field-file-add-more').attr('disabled','disabled').fadeTo(200,.20);
+        $('#edit-submit').attr('disabled','disabled').fadeTo(200,.20);
+        $('#edit-preview').attr('disabled','disabled').fadeTo(200,.20);
+        $('#edit-delete').attr('disabled','disabled').fadeTo(200,.20);
+      }
+    });
+  });
+}
+
+// Enable buttons
+Drupal.behaviors.readySave = function (context) {
+   var queued = 0;
+   $('.filefield-element .form-file').each(function() {
+      if (jQuery(this).val() != '') {
+         queued++;
+      }
+   });
+   if (queued === 0) {
+      $('#edit-field-file-field-file-add-more').removeAttr('disabled').fadeTo(200,1);
+      $('#edit-submit').removeAttr('disabled').fadeTo(200,1);
+      $('#edit-preview').removeAttr('disabled').fadeTo(200,1);
+      $('#edit-delete').removeAttr('disabled').fadeTo(200,1);
+   }
+}