There is a bug in DCC resuming where the ACCEPT message does not honor the "fill spaces" setting. For example:
[12:37:12] <- :ed!snow@vw29854.netspace.net.au PRIVMSG ash :DCC SEND Big_Train_-ep1.avi 167772161 48107 137207808
[12:37:12] -> netspace.vic.au.austnet.org PRIVMSG ed :DCC RESUME "Big_Train_-ep1.avi" 48107 72189690
[12:37:12] <- :ed!snow@vw29854.netspace.net.au PRIVMSG ash :DCC ACCEPT "Big Train -ep1.avi" 1030 72189690
This may seem insignificant, but on that particular IRC server, DCC privmsgs with spaces in the file name are blocked, thus the send failed. Also some other clients may not like having a different file name in the ACCEPT message.