Database connectivity error with ms-access

Database connectivity in matlab R2012a 64 bit in windows 7 64 bit using ms access 64 bit. i am getting error message when ping database is : Error using database/ping (line 105) Invalid connection. code used my me:

logintimeout(60);%60 second are alotted to establish connection between matlab and database
conn=database('db3','','');
setdbprefs('DataReturnFormat','cellarray');
ping(conn);%Error using database/ping (line 105) Invalid connection.

suggest me what is wrong in this code? thank you in adv.