I know that the premium downloader stores files on the server to save on bandwidth from repeat requests for the same files, so you can conserve your bw, and help keep mobilism's premium filehost accounts open as long as possible.
But I'd like to suggest that you maybe create some sort of table that shows when the file was originally downloaded and wipe the files a bit more often.
One problem that I've seen was where an uploader uses the same file name (usually something generic like a numbered filename, or a generic term like "fire.rar") as another uploader for a different book. Whichever one was downloaded first using the premium downloader will get saved in cache, and any future requests (even many weeks later) for the same file name from any host, even a different host, gets that same previous file.
Another problem I've been running into is where for whatever reason, the downloader got an incomplete file. The incomplete file is treated as complete, and served up for all future requests for that filename.
( see
https://rapidgator.net/file/61050294/light.rar.html for example, which is also a good example of a generic filename that could easily end up being part of the first noted issue).
More aggressively clearing out the cache of previously downloaded files would help greatly minimize this issue.
Just a suggestion from someone with a programming background, and someone who loves this site. I regularly check the files I download for accuracy, but someone else may not and may not understand why they got the wrong book, and blame the uploader.
--Shadowebs
PS
Note to any one reading who hasn't bought premium....
Premium is something anyone who regularly uses this site should get, even if you don't use the downloader much you're helping to support the site and keep it running, a very very small price to pay. And whenever there are problems, as you can see here, but also via Private Messages, the admins respond very quickly. Better than a lot of paid tech support staff on business sites.