Jared, thanks for the reply. Yes, I tested with an admin account. I disabled all plugins except bbpress and bbPress Enable TinyMCE Visual Tab. I also switched to the Twenty Twelve theme to ensure that nothing in my functions.php interferes. Still the same error.
It appears something is uploading because the speed of the progress bar depends on the file size. However, when the upload is finished I get the error message and no new files appear in the upload directory.
I tested with WordPress 3.5.1 and 3.5.2. bbpress version is 2.3.2. bbPress Enable TinyMCE Visual version is 1.0.0.
Thanks a lot! It seems you were right. I downloaded and uploaded again and now it works perfectly fine. I hope I didn’t trouble anybody. Sorry…
