c program problem

i am using at89c52. i compiled the below c program its showing error as given below whats is the error in this program

c(4): warning C318: can't open file 'usart.h'
c(5): warning C318: can't open file 'lcd.h'
c(6): warning C318: can't open file 'gsm.h'
c(47): warning C206: 'DelayMs': missing function-prototype
c(47): error C267: 'DelayMs': requires ANSI-style prototype

#include <at89c51xd2.h>
#include <string.h>
#include <stdio.h>
#include "usart.h"
#include "lcd.h"
#include "gsm.h"

// Inputs
#define moistureSensor1 P1_4
#define moistureSensor2 P1_5
#define moistureSensor3 P1_6
#define moistureSensor4 P1_7

//Outputs
#define relayMotor P0_0
#define NOR_CONDITION 1
#define DRY_CONDITION 2
#define WET_CONDITION 3

unsigned char fieldStatus = 0;

unsigned char motorOnFlag = 0;
unsigned char motorOffFlag = 0;
unsigned char moisSenCnt = 0;
unsigned char mtOnSmsFlag = 0;
unsigned char mtOffSmsFlag = 0;

unsigned char smsSendFlag = 0;
xdata unsigned char smsMessage[ 100 ];

void main( void )
{ xdata unsigned char messageBuffer[200]; int retValue = 0; unsigned char *myString1 = "Starting........"; unsigned char *myString2 = "................"; unsigned char *myString3 = "Wting 4 Command "; unsigned char *myString4 = "Command Recieved"; unsigned char colunCount = 0, index = 0; xdata unsigned char gsmCommand[7]; unsigned int waitCnt = 0;

P2 = 0xFF; P3 = 0xFF; relayMotor=0; Delay_Ms(5);

Lcd_Init(); SenStringToLcd ( 1, myString1 ); SenStringToLcd ( 2, myString2 );

smsSendFlag = 0;

USART_Init_9600();

retValue = DeleteSms(); if( retValue == 0 ){

SenStringToLcd ( 1, "GSM Modem is " ); SenStringToLcd ( 2, "Not Functioning " ); }

while(1){

moisSenCnt = 0; motorOnFlag = 0; motorOffFlag = 0;

SenStringToLcd ( 1, " Sensing field " ); SenStringToLcd ( 2, " Condition " ); DelayMs( 100 );

if( moistureSensor1 == 1 ) moisSenCnt++; if( moistureSensor2 == 1 ) moisSenCnt++; if( moistureSensor3 == 1 ) moisSenCnt++; if( moistureSensor4 == 1 ) moisSenCnt++;

SenStringToLcd ( 1, " Field Sensed " ); SenStringToLcd ( 2, "****************" );

fieldStatus = NOR_CONDITION;

if( moisSenCnt <= 2 ){ fieldStatus = DRY_CONDITION; motorOnFlag = 1; motorOffFlag = 0; relayMotor=1; SenStringToLcd ( 1, "Field Is In Dry " ); SenStringToLcd ( 2, " Condition " ); DelayMs( 300 ); } else{ fieldStatus = WET_CONDITION; motorOffFlag = 1; motorOnFlag = 0; relayMotor=0; SenStringToLcd ( 1, "Field Is In Wet " ); SenStringToLcd ( 2, " Condition " ); DelayMs( 00 ); } SenStringToLcd ( 1, "****************" ); SenStringToLcd ( 2, "****************" ); DelayMs( 100 );

SenStringToLcd ( 2, myString3 ); DelayMs( 100 ); SenStringToLcd ( 2, myString2 ); DelayMs( 100 );

retValue = 0; strcpy( messageBuffer, "\0" ); retValue = ReadSms( messageBuffer ); if( retValue == 1 ){

index = 0; colunCount = 0; waitCnt = 0; while( (colunCount < 6) && (waitCnt < 10000) ){ if( messageBuffer[ index ] == '"' ){ colunCount++; } index++; waitCnt++; }

SenStringToLcd ( 1, myString4 ); strcpy( gsmCommand, "\0" ); strncpy( gsmCommand, &messageBuffer[index+2],6 ); gsmCommand[6] = '\0'; SenStringToLcd ( 2, myString2 ); DelayMs( 10 ); SenStringToLcd ( 2, gsmCommand ); DelayMs( 250 );

if ( !strcmp( gsmCommand, "MTR ON" ) ){ relayMotor=1; motorOnFlag = 1; motorOffFlag = 0; SenStringToLcd ( 1, " MOTOR ON " ); SenStringToLcd ( 2, "****************" ); } else if ( !strcmp( gsmCommand, "MTR OF" ) ){ relayMotor=0; motorOffFlag = 1; motorOnFlag = 0; SenStringToLcd ( 1, " MOTOR OFF " ); SenStringToLcd ( 2, "****************" ); } else if ( !strcmp( gsmCommand, "GIFMOD" ) ){ smsSendFlag = 1; SenStringToLcd ( 1, "Request Received" ); SenStringToLcd ( 2, "****************" ); DelayMs( 100 ); } else{ SenStringToLcd ( 1, "Invalid Command " ); DelayMs( 200 ); SenStringToLcd ( 2, "Received " ); DelayMs( 200 ); }

if( smsSendFlag == 1 ){

smsSendFlag = 0;

if( fieldStatus == NOR_CONDITION ){ strcpy( smsMessage, "Field Is In Normal Condition." ); SendSms( "+919490045729", smsMessage ); DelayMs( 500 ); SendSms( "+919703935935", smsMessage ); DelayMs( 500 ); } else if( fieldStatus == DRY_CONDITION ){ strcpy( smsMessage, "Field Is In Dry Condition." ); SendSms( "+919490045729", smsMessage ); DelayMs( 500 ); SendSms( "+919703935935", smsMessage ); DelayMs( 500 ); } else if( fieldStatus == WET_CONDITION ){ strcpy( smsMessage, "Field Is In Wet Condition." ); SendSms( "+919490045729", smsMessage ); DelayMs( 500 ); SendSms( "+919703935935", smsMessage ); DelayMs( 500 ); } else{ } }

if( motorOnFlag == 1 && mtOnSmsFlag == 0){

motorOnFlag = 0; mtOnSmsFlag = 1; mtOffSmsFlag = 0; strcpy( smsMessage, "Motor On In the field" ); SendSms( "+919490045729", smsMessage ); DelayMs( 500 ); SendSms( "+919703935935", smsMessage ); DelayMs( 500 ); } if( motorOffFlag == 1 && mtOffSmsFlag == 0){

motorOffFlag = 0; mtOffSmsFlag = 1; mtOnSmsFlag = 0; strcpy( smsMessage, "Motor Off In the field" ); SendSms( "+919490045729", smsMessage ); DelayMs( 500 ); SendSms( "+919703935935", smsMessage ); DelayMs( 500 ); }

SenStringToLcd ( 1, "Command Executed"); DelayMs( 300 );

while( DeleteSms() == 0); SenStringToLcd ( 1, "Command Deleted "); SenStringToLcd ( 2, myString2 ); } } // End Of while(1);
}