Put keyboard text on gui

When I use the module Dirty Larry I have this error:

ERROR:SCRIPT: main/lua/dirtylarry.lua:108: No such node: username/bg
stack traceback:
[C]: in function 'get_node’
main/lua/dirtylarry.lua:108: in function 'input’
main/lua/username.gui_script:12: in function <main/lua/username.gui_script:11>