Where did I go Wrong on this coder?

I am using DevC++ and have saved it as a C file. I keep getting an error [Error] Id returned 1 exit status. It wont compile. I am learning and am stumped. I also have this other error that states. undefined reference to 'If', so do I then define it with a variable? If you can inform me on this that would be awesome.

/*Program: Coder.c
*Usage: Coder [filename] [action]
where filename = filename for/with coded data
where action = D for decade anything else for
coding
........................................................../

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int encode_charactoer( int ch, int val );
int decode_character( int ch, int val );

int main( int argc, char argv[])
{
FILE fh; /file handle/
int rv = 1; /return value/
int ch =0; /variable to hold a character/
unsigned int ctr = 0; /counter/
int val = 5; /value to code with/
char buffer[257]; /buffer/

if( argc != 3 )
{
    printf("\nError: Wrong number of parameters...");
    printf("\n\nUsage:\n  %s filename action", argv[0]);
    printf("\n\n   Where:");
    printf("\n        filename = name of file to code or decode");
    printf("\n        action   = D for decode or C for encode\n\n");
    rv = -1;       /*set return error value*/
}
else
if ((argv[2][0] == 'D') || (argv [2][0] == 'd' )) /*to decode*/
{
    fh = fopen(argv[1], "r");   /*open the file */
    if( fh <= 0 )               /*check for error */
    {
        printf( "\n\nError opening file..." );
        rv = -2;               /*set return error value*/
    }
    else
    {
    ch = getc( fh );           /*get a character*/
    while( !feof( fh ))        /*check for end of file*/
    {
        ch = decode_character( ch, val );
        putchar(ch);  /*write the character to screen*/
        ch = getc( fh);
    }
    
    fclose(fh);
    printf("\n\nFile decoded to screen.\n" );
}

}
else /assume coding to file./
{

fh = fopen(argv[1], "w");
if ( fh <= 0 )
{
    printf("\n\nError creating file...");
    rv = -3; /*set return value*/
 }
 else
 {
    printf("\n\nEnter text to be coded. ");
    printf("Enter a blank line to end.\n\n");
    
    while( gets(buffer) != NULL )
    {
        If( buffer[0] == 0 );
             break;
             
        for( ctr = 0; ctr < strlen(buffer); ctr++)
        {
            ch = encode_character( buffer[ctr], val );
            ch = fputc(ch, fh);    /*Write the character to file*/
         }
     }
     printf("*\nFile encoded to file.\n");
     fclose(fh);
 }
 
}
return (rv);

}

int encode_character( int ch, int val )
{
ch = ch + val;
return (ch);
}

int decode_character( int ch, int val )
{
ch = ch - val;
return (ch);
}