We are using Tridion 2011 SP1 in combination with Tridion UI 2012.
I had definied a bunch of content types in the publication properties to be used inside the UI interface. At one point a referenced component was deleted, which apparently is possible, even though it is referenced inside the Content Types overview.
But, ever since when exporting and importing using the Content Porter I have been getting the error:
Unable to resolve WebDav URL for item "tcm:1-2345". referenced in application data. It will be ported as is.
It will let me export and import, but with errors...
The whole Tridion UI 2012 application seems to be based on configs and webdav urls stored as some sort of data file, but I cannot seem to update, or clear this error.