want to declare an ifstream as part of my class

hello

whne I declare a member of type ifstream in my class, I get errors such as:

error: within this context
/usr/lib/gcc/i386-redhat-linux/3.4.2/../../../../include/c++/3.4.2/streambuf: In member function `std::basic_filebuf<char, std::char_traits<char> >& std::basic_filebuf<char, std::char_traits<char> >::operator=(const std::basic_filebuf<char, std::char_traits<char> >&)':
/usr/lib/gcc/i386-redhat-linux/3.4.2/../../../../include/c++/3.4.2/streambuf:776: error: `std::basic_streambuf<_CharT, _Traits>& std::basic_streambuf<_CharT, _Traits>::operator=(const std::basic_streambuf<_CharT, _Traits>&) [with _CharT = char, _Traits = std::char_traits<char>]' is private

and this happens if I just declare something of type ifstream as one of my public member variables , like so:

#include <iostream>
#include <fstream>
using namespace std;

class SOMECLASS
{
    void blabla()
    ifstream infile;
};

I'm on a linux, why doesnt it like this?????
Thank you in advance!!
LD