Thread: fatal error C1001

I am getting an error:

cpp1.cpp(18) : fatal error C1001: INTERNAL COMPILER ERROR
(compiler file 'msc1.cpp', line 1794)

I think this may have something to do with my header files, but they are included correctly.

Code:

#include <iostream.h>
#include <fstream.h>
#include <ctype.h>
#include <iomanip.h>
#include "student.h"
#include "StudentLinkList.h"

//Main function

int main(void)    //This is line 18
{
	char cmd;
	do{
		cout << "Please enter a command: R)ead, L)ist, G)rades, A)dd, D)elete, S)ave, or Q)uit" << endl;
		cin >> cmd;
		switch ( cmd = toupper(cmd))
		{
		case 'R':
			s.ReadFile ();
			break;
		case 'L':
			s.List ();
			break;
		case 'G':
			s.Grades ();
			break;
		case 'A':
			s.Add ();
			break;
		case 'D':
			s.Delete ();
			break;
		case 'Q':
			break;
		case 'S':
			s.Save ();
			break;
		default:
			cout << "Invalid Command. ";
		}
	}while(cmd!='Q');
	return 0;
}