PC doesn't receive packets from Nios II

Hi, I need to send data from de2-115 to PC using triple speed ethernet core, and then process the data using a program which I wrote using Qt. I manage to make it work sending the data to the pc. Wireshark show the data arrive but with bad frame check sequence. I think it's the reason why the program couldn't read the packets. Anyone has any idea to fix this?

Here is my code for my udp ethernet.