That's sort of a bug. ImageGallery and DOM are moving to Uploadify as the preferred upload plugin, and I'm gradually going to deprecate SWFUpload. ImageGalleryAlbum should be checking which one is installed rather than assuming Uploadify.

So the easiest thing to do is to install Uploadify for now.

http://www.leftandmain.com/silverstripe-modules/2010/08/26/uploadify/

---------------
Silverstripe tips, tutorials, screencasts, and more. http://www.leftandmain.com

Ok thx, uploaded/installed uploadify,

I can access the CMS now,
but when I save the page the CMS says: 'Error saving document' (in the left corner)

Why is this?

note: Also uploaded 10 photos into an a new album, but after succesfull upload the thumbs are not visible in the CMS album.

Can you look at the response and find out what error is?

---------------
Silverstripe tips, tutorials, screencasts, and more. http://www.leftandmain.com

Where can I find this response?

Ok maybe this helps:

When I try to add a existing photo to a existing album
(Tab: Photos > Add images to "default album" > Tab: Choose existing > Select Folder > click on a the photo > continue)

[Notice] Trying to get property of non-object
POST /admin/EditForm/field/GalleryItems/UploadifyForm?ctf[GalleryItems][start]=0&ctf[GalleryItems][per_page]=10&ctf[GalleryItems][showall]=0&ctf[GalleryItems][sort]=SortOrder&ctf[GalleryItems][sort_dir]=&ctf[GalleryItems][search]=&ctf[GalleryItems][filter]=AlbumID_3&ctf[GalleryItems][view]=grid&ctf[GalleryItems][imagesize]=100

Line 140 in /sites/url.nl/www/image_gallery/code/ImageGalleryManager.php


Source

131 	{
132 		$childData = parent::getChildDataObj();
133 		$childData->ImageGalleryPageID = $this->controllerID;
134 		return $childData;
135 	}
136 	
137 	public function getPreviewFieldFor($fileObject, $size = 150)
138 	{
139 		if($fileObject instanceof Image) {
140 			$URL = $fileObject->SetHeight($size)->URL;
141 			return new LiteralField("icon",
142 				"<div class='current-image'>
143 					<div id='preview-image'>
144 						<img src='$URL' alt='' class='preview' />
145 						<div class='ajax-loader'><img src='dataobject_manager/images/ajax-loader.gif' />". _t('ImageGalleryManager.ROTATING','Rotating')."...</div>
146 					</div>

Trace

    * ImageGalleryManager->getPreviewFieldFor(ImageGalleryImage)
      Line 512 of FileDataObjectManager.php
    * FileDataObjectManager->EditUploadedForm()
      Line 436 of FileDataObjectManager.php
    * FileDataObjectManager->saveUploadifyForm(Array,ImageGalleryManager_Popup,SS_HTTPRequest)
      Line 300 of Form.php
    * Form->httpSubmission(SS_HTTPRequest)
      Line 137 of RequestHandler.php
    * RequestHandler->handleRequest(SS_HTTPRequest)
      Line 155 of RequestHandler.php
    * RequestHandler->handleRequest(SS_HTTPRequest)
      Line 155 of RequestHandler.php
    * RequestHandler->handleRequest(SS_HTTPRequest)
      Line 155 of RequestHandler.php
    * RequestHandler->handleRequest(SS_HTTPRequest)
      Line 147 of Controller.php
    * Controller->handleRequest(SS_HTTPRequest)
      Line 281 of Director.php
    * Director::handleRequest(SS_HTTPRequest,Session)
      Line 124 of Director.php
    * Director::direct(/admin/EditForm/field/GalleryItems/UploadifyForm)
      Line 127 of main.php

has anyone found a solution for that? :/

Please help to solve the error. thanks

ERROR [User Error]: collateDataFields() I noticed that a field called 'Priority' appears twice in your form: 'Form_EditForm'. One is a 'DropdownField' and the other is a 'DropdownField'
IN POST /SilverStripe/admin/getitem?ID=6&ajax=1
Line 140 in C:\xampp\htdocs\SilverStripe\sapphire\forms\CompositeField.php

Source
======
131: if($saveableOnly) {
132: $isIncluded = ($field->hasData() && !$field->isReadonly() && !$field->isDisabled());
133: } else {
134: $isIncluded = ($field->hasData());
135: }
136: if($isIncluded) {
137: $name = $field->Name();
138: if($name) {
139: $formName = (isset($this->form)) ? $this->form->FormName() : '(unknown form)';
* 140: if(isset($list[$name])) user_error("collateDataFields() I noticed that a field called '$name'
appears twice in your form: '{$formName}'. One is a '{$field->class}' and the other is a
'{$list[$name]->class}'", E_USER_ERROR);
141: $list[$name] = $field;
142: }
143: }
144: }
145: }
146: }

Trace
=====
<ul>user_error(collateDataFields() I noticed that a field called 'Priority' appears twice in your form: 'Form_EditForm'. One is a 'DropdownField' and the other is a 'DropdownField',256)
line 140 of CompositeField.php

CompositeField->collateDataFields(Array,)
line 130 of CompositeField.php

CompositeField->collateDataFields(Array,)
line 130 of CompositeField.php

CompositeField->collateDataFields(Array,)
line 66 of FieldSet.php

FieldSet->collateDataFields(Array)
line 50 of FieldSet.php

FieldSet->dataFields()
line 929 of Form.php

Form->loadDataFrom(SlideShowProPage)
line 493 of CMSMain.php

CMSMain->getEditForm(6)
line 1021 of LeftAndMain.php

LeftAndMain->EditForm()
line 382 of LeftAndMain.php

LeftAndMain->getitem(SS_HTTPRequest)
line 193 of Controller.php

Controller->handleAction(SS_HTTPRequest)
line 137 of RequestHandler.php

RequestHandler->handleRequest(SS_HTTPRequest)
line 147 of Controller.php

Controller->handleRequest(SS_HTTPRequest)
line 281 of Director.php

Director::handleRequest(SS_HTTPRequest,Session)
line 124 of Director.php