troubleshooting runtime error class not registered 

Try re-registering the Msado15.dll file. Click on Start > Run. Then enter
the command:

Regsvr32 "C:\Program Files\Common Files\system\ado\Msado15.dll"

Just for good measure, do the same thing with your DAO360 file (it won't
hurt anything to re-register a file that is correctly registered):

Regsvr32 "C:\Program Files\Common Files\Microsoft Shared\DAO\Dao360.dll"

If your copies of Msado15.dll and/or Dao360.dll are in different folders,
then make the necessary adjustments to the paths indicated above. Make sure
to include quotes around the paths.