I have the same error. Also popped up seemingly randomly.
More info: I get the same error described above. The ‘Add Gallery/Images’ page displays the error and shows a yellow triangle with an exclamation point next to each image. The page reports that no images were uploaded. When I look on the ‘Manage Galleries’ page it has actually created a new gallery for each image uploaded. If I create a gallery called ‘Photos’ and upload 10 images to it I will have ten gallery’s (each with a unique ID) called ‘Photos’, each with one image in it.
If I add images to an existing gallery the ‘Add Gallery/Images’ page reports an error but the images (most of them …usually) do actually upload into the gallery.
The only way I can get multiple images into a gallery is to create a gallery, adding only one image when created and then go back and add all of the other images. I get errors telling me it failed but the images are uploading (but it does seem to randomly fail).
