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I have a similar problem as described ....
I created an upload directory and upload a bunch of .jpgs ~75KB in size. In file manager I can see the images in the correct upload directory and I can click on them and they display as expected.
I created a channel that has a file field type. In the process of publishing the entry, I click the “add file” link to fill in the file field, and the file manager overlay appears with a list of images for the files I previously uploaded. First thing I note is the images themselves are not displayed, just white boxes with the name below. If I click on the file I want to add the entry shows the same white box image with the text “undefined” beneath. If I try and submit the entry I get an error saying the file filed is empty.
If I peruse another previously created upload directory I can see the images when I select the directory and I can select them for the file field type. So there is something awry with this upload directory. I checked the permissions, both 705.
I did try to upload a file from a remote server when adding a file to the file field and it worked. However, if I edit the same entry and try to re-add the same file from the upload directory I get the undefined error again.
I have a simple installation ...
EE 2.1.3 Build: 20110411
WYGWAM