It looks like you have gone one too many directories up. I presume the "db" folder is inside of the "masterasp" folder? If so, then try the following:
include '/db/conn.php'; #should also work
include 'db/conn.php'; #should again work
By deleting one of the front periods, we are now searching for the "db" folder inside of the current directory, rather than heading one directory up into the main domain folder when searching for you "db" folder.
You could also use an absolute path, instead of calculating the whereabouts of the connection file relative to the file system you are working in.