but i don't have any document like .festivalrc in home dirctory
i was created one document in home directory with file name .festivalrc
and i copied above two lines in that document and saved
It most likely has to do with permissions on the file. Typically only root can access a directory like that. I would suggest change the permissions on it by starting your file manager as root. Right clicking the directory and giving read and write access to all users. Or if the directory does not exist create it with the following command: sudo mkdir /dev/dsp
or use sudo festival assuming "festival" is the name of the program. This will run festival as root.