I've just released udpcast 20081116, which has a work-around for that llseek bug in the kernel. The bug has also been reported to the kernel mailinglist and will (hopefully) be fixed in one of the next kernels...
Moreover, udpcast now has a new --stat-period flag, which allows to specify how often statistics are refreshed (expressed in milliseconds, default is half a second)
Regards,
Alain