I don't use mobile phone for any kind of forums so those options are out for me.
I only use Windows PC for such activities including Craxme fforum and prior to that the UCWEB. In both instances I hav had one major problem. I cannot upload any books or for that matter any image also, even if it is 400 KB size. When I click on the browse button for attachment and select a file, I get the "Server I/O error". Every time.
I have tried to add the screenshot. If it doesn't show up, then the link is: https://imgur.com/a/AfZGT
Any solution? This is since the ucweb days and I have not found a solution so far! Hence can't upload books also. If I use another sharing site for books, the link will expire in 30 days!