[How to edit .lub files?]

Hi i'm having difficulty opening the .lub (i'm already using GRF editor) file since i'm having an issue on 3rd job skills 

can someone please help teach me a step by step to do this? I'm stuck already. Thanks in advance.

[Server Recieved Crash Signal - Female Shura]

I'm having error  Server Recieved Crash Signal upon loading my new changed job Female Shura,. i'm just playing solo btw. When i restart the server and choose my other character/s it works just fine..

Any suggestions how to fix this? i was really looking forward to check some 3rd job skills.. :(