>> and << are operators that are generally valid for streams (cout and cin are actually file streams). You should be able to use >> with ifstream, as per
this page (ifstream is derived from istream). That site is a good reference to use.
I have no idea what that error means.
To use a different debugger, you would have to compile with a different compiler. Microsoft's VC++ 7.1 compiler is free to get (the command line version), which you should be able to plug in to DevC++ (if it is worth it's salt).