Unable to connect to Oracle from SQL Developer
This seems to be a hostname resolution problem. Please try to connect to the IP address instead of the hostname.

If this is not the solution could you please post the output of the following command:

lsnrctl status


EDIT 1:

LISTENER = 
(DESCRIPTION_LIST = 
  (DESCRIPTION = 
    (ADDRESS = 
      (PROTOCOL = IPC)(KEY = EXTPROC1521)
    )
    (ADDRESS = 
      (PROTOCOL = TCP)(HOST = 192.168.2.64)(PORT = 1521)
    )
  )
)


EDIT 2:

It turned out to be an firewall problem. See comments below.