It's unable to resolve a host!

Ok i'm trying to upload my files onto a new website [i don't really kno how to work FTP cause i'm new at it]. It's hosted by someone so i'm a hostee. My host told me that in the address bar i should put [<---that's an example; i'm gonna b using examples;] and in the login i should put and in the password i should put my password. and it doesn't go through! This is what it always says:
SmartFTP v2.0.996.28
Resolving host name ""
Unable to resolve host name.
Active Help:
Cannot login waiting to retry (30s)...
And everytime it makes its attempt to retry it always fails. am i doing something wrong?