[OpenSER-Users] call functions with Perl (moduleFunction())

Hi, Please, i want to know why when i try to use remove_hf() and append_hf() functions with Perl (moduleFunction(func,string1,string2)), I have this message: Jun 12 11:03:53 [12838] ERROR:core:moduleFunc: Module function 'remove_hf' is unsafe. Call is refused. Jun 12 11:03:53 [12838] ERROR:core:XS_OpenSER__Message_moduleFunction: calling module function 'remove_hf' failed. Missing loadmodule? Jun 12 11:03:53 [12838] ERROR:core:moduleFunc: Module function 'append_hf' is unsafe. Call is refused. Jun 12 11:03:53 [12838] ERROR:core:XS_OpenSER__Message_moduleFunction: calling module function 'append_hf' failed. Missing loadmodule? Thanks, Yazid