If you are using Packet Obfuscation, please put the right keys when you diff your client.exe and disable 'Disable Packet Encrypt'. Default keys for 2013-08-07Ragexe is 0x7E241DE0,0x5E805580,0x3D807D80.
If you are not using the Packet Obfuscation, when you diff your client.exe please enable 'Disable Packet Encrypt' and go to your src/config/core.h and find
/// Comment to disable the official packet obfuscation support.
/// When enabled, make sure there is value for 'packet_keys' of used packet version or
/// defined 'packet_keys_use' in db/[import/]packet_db.txt.
/// This requires PACKETVER 2011-08-17 or newer.
#define PACKET_OBFUSCATION
disable it by commenting '//' at #define PACKET_OBFUSCATION
Edit : use NEMO patcher for diffing your client.exe.