Have this Problem on 2 PC´s in the same Subnet - uplay says (since monday) there´s a Patch v.1.5 and when I start downloading it shows "Download failed". Already made a Ticket (01838723) but no reaction from ubisoft Support. Both PC´s working fine in all other games, steam, origin, uplay, etc...
What´s wrong with you Ubi guys ?
http://forums.ubi.com/showthread.php...1#post10378063
Check Amyez's post. I got a download error (screenshot in my post in that thread) for the 1.4 patch and his workaround got it going for me. May help for you also.