[Udpcast] udpcast 20110710 too re-xmits

Hi Sorry for my English. I have been using udpcast (PXE or a custom Debian Live) over the past two years (version 20100130) and I recently upgraded to the latest version ( 20110710), the old version got a transfer rate of about 480Mbps, with feww reemissions (approximately 10 re-xmits) with the new and the same teams involved does not exceed 43 Mbps. I tried to disable ipv6 (ipv6.disable = 1) but there was no difference. If I use the udp-sender (20110710) with the udp-receiver (20100130) recovered the rate of 480 Mbps. How do I find out why the number of re-xmits increases significantly? Thanks in advance