I suggest to use configuration. Configure the connection string of OLEDB server and place the below string for connection string.

Data Source=SERVERNAME\INSTANCENAME;User ID=UserID;Pwd=XXX;Initial Catalog=DATABASENAME;Provider=SQLNCLI.1;Persist Security Info=True;Auto Translate=False;

Hope this helps.

The meta data of excel source should match with the table meta data. If the meta data is not matching you can change the meta data in the advance editor...

Is integration services running on your machine? If yes, try to connect the integration services from management studio by giving the server name(in your case computer name) don't put instance...