ALV editable with error lvc_t_style

Hi experts!!!

I have a problem, I need develop an alv editable and i've read the solutions you have proposed in another threads, my problem is when i declare "celltab" type lvc_t_styl, the check syntax tell 'the type "lvc_t_styl" is uknown.

Do you have any idea why this error???

thanks!!.

Antonio Piñ