First, if you have an error message saying 'a nil value' that's a LUA/LUB error, make sure you put your LUA/LUB in the correct folder, (ex: C:\kRO\data\luafiles514\lua files)
Second, try to rediff your client.exe without "read data folder first" and "read lua before lub", and be sure to use "WDGSkipPacketHeaderObfuscation.dll" option from earthlingz.
Third, after you make changes to mmo.h, don't forget to recompile your server again.
Fourth, don't forget to edit your address IP and port in clientinfo.xml to match your server IP.
<address>"MyIP"</address>
<port>"myport"</port>