After a second thought, I think I know what is the problem with mediafire; it probably doesn't like .7z files compression:
TDW's mods whose mediafire links stopped working recently have this extensionn.
So far I have always used the rar format for my files uploaded on mediafire (including the previous version of DynEnv, which incidentally had a bigger filesize than the current one), and had no problems with them.
This is the first time I use the .7z format and the download gets broken after few downloads
