TFTP load balancing

Hi Guys Is this working for you? I tried to use it as I have a TFTP server that I have to load-balance! I used UDP 69 but and I applied the rule but I see in the logs this : TFTP notice: failed to open listener for xxxxxxx%1:54865 TFTP notice: failed to open listener for xxxxxxxxx%1:2164 TFTP notice: failed to open listener for xxxxxxxxx%1:54865

I mention that before applying the iRule I managed to have the file on the TFTP server but with 0kb. In the tcpdumps on the F5 I've seen this: write request which is hitting the server. server ack and then the serverr is sending opcode 5 and an "undefined error" opcode 5 in TFTP is a TID (transfer ID)