KenF:
Well before you waste the next couple of days. This might get you close. I don't have any hardware to test it on so it may take a bit of debugging.
/*--------------------------------------------------------------
Program: eth_websrv_SD
Description: Arduino web server that serves up a basic web
page. The web page is stored on the SD card.
Hardware: Arduino Uno and official Arduino Ethernet
shield. Should work with other Arduinos and
compatible Ethernet shields.
2Gb micro SD card formatted FAT16
Software: Developed using Arduino 1.0.3 software
Should be compatible with Arduino 1.0 +
SD card contains web page called index.htm
References: - WebServer example by David A. Mellis and
modified by Tom Igoe
- SD card examples by David A. Mellis and
Tom Igoe
- Ethernet library documentation:
Ethernet - Arduino Reference
- SD Card library documentation:
SD - Arduino Reference
Date: 10 January 2013
Author: W.A. Smith, http://startingelectronics.com
--------------------------------------------------------------*/
#include <SPI.h>
#include <Ethernet.h>
#include <SD.h>
// MAC address from Ethernet shield sticker under board
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress ip(10, 10, 1, 222); // IP address, may need to change depending on network
EthernetServer server(80); // create a server at port 80
File webFile;
void setup()
{
Ethernet.begin(mac, ip); // initialize Ethernet device
server.begin(); // start to listen for clients
Serial.begin(9600); // for debugging
// initialize SD card
Serial.println("Initializing SD card...");
if (!SD.begin(4)) {
Serial.println("ERROR - SD card initialization failed!");
return; // init failed
}
Serial.println("SUCCESS - SD card initialized.");
// check for index.htm file
if (!SD.exists("index.htm")) {
Serial.println("ERROR - Can't find index.htm file!");
return; // can't find index file
}
Serial.println("SUCCESS - Found index.htm file.");
}
void loop()
{
String requestString = "" ;//String to store chars
EthernetClient client = server.available(); // try to get client
if (client) { // got client?
boolean currentLineIsBlank = true;
while (client.connected()) {
if (client.available()) { // client data available to read
char c = client.read(); // read 1 byte (character) from client
// last line of client request is blank and ends with \n
// respond to client only after last line received
requestString = requestString + c;
if (c == '\n' && currentLineIsBlank)
{if (requestString.indexOf("dygraph")>0)
{// send a standard http response header
client.println("HTTP/1.1 200 OK");
client.println("Content-Type: text/plain");
client.println("Connection: close");
client.println();
webFile = SD.open("dygraph.js"); // open web page file
if (webFile) {
while(webFile.available()) {
client.write(webFile.read()); // send web page to client
}
webFile.close();
}
else
{
// send a standard http response header
client.println("HTTP/1.1 200 OK");
client.println("Content-Type: text/html");
client.println("Connection: close");
client.println();
// send web page
webFile = SD.open("index.htm"); // open web page file
if (webFile)
while(webFile.available())
client.write(webFile.read()); // send web page to client
webFile.close();
}
}
break;
}
// every line of text received from the client ends with \r\n
if (c == '\n') {
// last character on line of received text
// starting new line with next character read
currentLineIsBlank = true;
}
else if (c != '\r') {
// a text character was received from client
currentLineIsBlank = false;
}
} // end if (client.available())
} // end while (client.connected())
delay(1); // give the web browser time to receive the data
client.stop(); // close the connection
} // end if (client)
}
Thank you for the code, and for your time in putting my IP address and filenames in.
It compiles easy enough, but I think you might be right about the debugging..!
When I upload this code i get this screen when I browse to the IP address of the arduino:
I'm comparing it against a working sketch at the moment. 
