help with CGI script in C

I have the following code written to search a document for occurances of a string ( eventually will be searching a folder of documents, but thats another problem)
This code works perfect when compiled in Visual C++ but when I try to convert to cgi, the first strstr line lets me down......absolutely lost on this one......
Cheers............................PJG
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAXLEN 80
#define EXTRA 5 /* 4 for field name "data", 1 for "=" */
#define MAXINPUT MAXLEN+EXTRA+2 /* 1 for added line break, 1 for trailing NUL */


void unencode(char *src, char *last, char *dest)
{
for(; src != last; src++, dest++)
if(*src == '+')
*dest = ' ';
else if(*src == '%') {
int code;
if(sscanf(src+1, "%2x", &code) != 1) code = '?';
*dest = code;
src +=2; }
else
*dest = *src;
*dest = '\n';
*++dest = '\0';
}


int main(void)
{ /* begin program */



char line[250];
const char *delimiters = {" \t \n "};
char *token=NULL;
char* pStr = NULL;
int count = 0, line_count=0;
char *test = "";
FILE *essay;
char *lenstr;
char input[MAXINPUT], data[MAXINPUT];
long len;


printf("%s%c%c\n",
"Content-Type:text/html;charset=iso-8859-1",13,10);
printf("<TITLE>Response</TITLE>\n");


lenstr = getenv("CONTENT_LENGTH"); /* Getting string from HTML page */

if(lenstr == NULL || sscanf(lenstr,"%ld",&len)!=1 || len > MAXLEN) /*verifying that string is valid*/
printf("<P>Error in invocation - wrong FORM probably.");


else { /* begin ELSE */

fgets(input, len+1, stdin);
unencode(input+EXTRA, input+len, data);



if ((essay = fopen("C:/Inetpub/wwwroot/cgi-bin/stroke.txt", "r")) == NULL )
{
printf("<h2>File could not be opened - ask yourself WHYYYYY?");
}
else



while (!feof(essay))
{
if( fgets(line, 250, essay) != NULL )
{


pStr = line;
line_count++;


if (( test = strtok(pStr, delimiters )) != NULL )
{

if(strstr(test,data) !=NULL)



{

count++;
printf("<P>Entry %d on line %d: %s<br>", count, line_count, data);
}

while (( test = strtok((char *)NULL, delimiters )) != NULL)
{
if ( strstr(test,data) != NULL)
{
count++;
printf("<P> Entry %d on line %d: %s<br>", count, line_count, data);
}
}
}
}


}

printf("<H3>Files were searched successfully.... how about that!");
printf("<P>The string <H4>%s</H4> occurs %d times in %s <BR>", data, count, essay);

fclose(essay);

count =0;


}


return 0;
} /* End Program */

Does it work if you do not call unencode() ?