ARM7LPC2368Eclipse+ webdemo ping issue

HI,
I am usiing the ARM7_LPC2368_Eclipse+ webdemo for Embedded artist LPC2468 board.i have modified the emac.c file for macrel phy.(EA using macrel phy) i could receive the ping packet but its not transmitting back.Using the IP address 192.168.1.100 and  192.168.1.103 and netmask 255.255.255.0. with direct cross cable.
i have 2 issues
1.  packet is not transmitting from board(receiving correctly,enabled the tx register,correct destination address)
2  #defined Ip address(uIP_task.c) of board is changing after some duration. has anybody using the same board and faced the issue.please give your suggestions regarding the issue
thanks