Can you supply the servername and the instance name if it is not the default instance on the server. This will help us format the SQLCMD parameters you should be using.

Generally when I have used it is has been:

sqlcmd -H<Host name if on different machine> -S<SQL server name\instance name> -U<username if needed> -P<password> -E -i<input file for execution> -o<output file for results>