Problem with namespaces

Hello all,

I am having a problem with the following program on AIX:-

// Namespace.cxx
#include <iostream>
using namespace std;
#include <iostream.h>
int main()
{
// cout<<"Hello world";
return 0;
}

On compilation:-
$ xlC Namespace.cxx
"/usr/vacpp/include/iostream.h", line 114.38: 1540-0063 (S) The text "*" is unexpected.
"/usr/vacpp/include/iostream.h", line 300.25: 1540-0040 (S) The text "seekoff" is unexpected. "streampos" may be undeclared or ambiguous.
"/usr/vacpp/include/iostream.h", line 443.32: 1540-0600 (S) The reference to "ios" is ambiguous.
"/usr/vacpp/include/iostream.h", line 78.7: 1540-0425 (I) "ios" is defined on line 78 of "/usr/vacpp/include/iostream.h".
"/usr/vacpp/include/iosfwd", line 330.45: 1540-0425 (I) "std::ios" is defined on line 330 of "/usr/vacpp/include/iosfwd".

Can anyone explain the reason for these strange looking errors? Please try out the different combinations of first 3 lines of the program and commenting and un-commenting the cout line in the main().

Regards,
Gupta