The ftp server is broken. This is caused by libraries being replaced by Ubuntu upgrades with libraries no longer compatible with the libraries it was compiled against. Further, the existing source for wu-ftpd will no longer compile in the modern compile environment so I can not fix it as I have done in the past. The last update to the source was in 2006 so this is not likely to be fixed and I will need to move to a newer ftpd, recommendations are welcomed. In the meantime please use scp or other file transfer protocols.