If you only have samba libs, and not cifs-utils installed, you will get:

mount: block device //10.0.64.60/linux is write-protected, mounting read-only
mount: cannot mount block device //10.0.64.60/linux read-only

So install cifs-utils ;).

Also make sure you do not have special characters in your username and password. CIFS really does not like backslashes. Remove the last newline if you use a credentials file and that is ASCII without \r’s.

Finally, make sure connectivity is OK.