I just got the information from a customer that a feature in the Telerik placeholder control can lead to broken resource links on the live site and to the following error message during authoring mode:
Save Placeholder Failed
The current user does not have rights to edit the requested item. If you are seeing this exception when a MCMS template is executing, it means that you have removed the CmsAuthorizationModule from the HttpModules section of your web.config. You can only remove this module if: 1. All requests for every MCMS template in the web application will only be accessed by anonymous users 2. Guest access is enabled in MCMS (via the SCA) 3. The MCMS guest user has access to all postings based on templates in the web application If any of these requirements are not met, you MUST register the CmsAuthorizationModule in your web.config.
The feature that causes this problem is the Overwrite if file with such name exists feature in the Telerik control. This control deletes the original item and uploads a new items. As this feature does not use the SetContentFromFile function in the API this will lead to a new, independend resource with a different GUID. All links in existing postings which point to the original resource gallery item will now reference the deleted item which causes this problem.
Telerik has been made aware of this problem and they will hopefully release a correct this code soon to ensure that the SetContentFromFile function is used rather than delete and upload.
Meanwhile you should not use the Overwrite if file with such name exists function in Telerik Control if postings use the original resource gallery item.