On Windows 7 (don't know about other Windows versions and OSes), when the path is too long, SABnzbd 0.7.0 (and previous versions) is reporting a disk error and stops the whole download queue when instead it should report a "path too long" error for hat specific download and continue with the rest of the queue.
My temporary download folder is something like "d:\temporary downloads". A download's path in that directory is automatically named after the newsgroup posting and reads something like "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" (modified for privacy purposes; the length of the path is the only interesting thing here). And of course the uploader deemed it necessary to name his files similarly exhaustively.
That's "d:\temporary downloads\xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.rar" as the file name. 272 characters.
Of course any action done on a path > 256 characters will fail. But it is not a disk error that requires stopping all downloads, it's a limitation in Windows and a screwup on the uploader's side for one single download. So please change the error message to something that reflects the actual error, point out the folder_max_length setting and let SABnzbd continue on other downloads.