Error on renaming client window name

[louigui]

im having problem on renaming the client window name

this is the steps that i do

i open HxD and then i open my client and press ctrl+F finding my client name Ex:myRO

then i click to the !st letter in letter m then i type my ro name ClientRO

and i save it but when it save this client is not turn to ragnarok icon and when i open it it causes a error. what is the problem?