I tried a capture on both end, and I'm basically seeing the same :
(Alcatel is 194.x.x.131/132, Phone is 172.x.x.1)
Alcatel side :
http://imgur.com/a/WrwOY
Phone side :
http://imgur.com/a/ttkUj
We can see that it's requesting the lanpbx.cfg and then it's when it's trying to download the starttscip that it's failing for some reasons.
I tried various sizes for the ping, but it does not seems to be fragmented, at least I can't see the DF flag in the Wireshark capture.