Here's a fix for Melbourne Cup Challenge that removes the disc protection and allows you to play from hard drive. This is for the PAL version. If anyone gets a chance to try it on the NTSC version (which I think is called Frankie Dettori Racing), let me know if it works.

# Game: Melbourne Cup Challenge (PAL)
# Title ID: 48450004
# Size: 1457MB (665 folders, 4834 files)
# Date: Jan 11, 2011
# Author: Lord Crass

# Disables DVD-check and allows play from hard drive

# Make a backup of the default.xbe file
CP|${DEST}\default.xbe|${DEST}\default.xbe_orig|

# This patch assumes that you have copied the disc to the XBox hard drive with DVD2Xbox
# and that the long file names (64 characters) are truncated to 42 characters.

# Knock out call to cdrom0: check and set proper flags
HR|default.xbe|1|52C605883D480001E8AB28140083C404|90C605883D48000131C0909090909090|
# Redirect call to file rename code
HR|default.xbe|1|E867290000|E88E420000|
# Add code to truncate file names on-the-fly in memory as they are used
HR|default.xbe|1|568B7424085756BF01000000|9C608B750831C931D28A0431|
HR|default.xbe|1|C70600000000E819FEFFFF|84C074093C5C750289CA41|
HR|default.xbe|1|83C40485C0750233FF6A00|EBF029D183F92B7E05C644|
HR|default.xbe|1|6A01E837FFFFFF83C408|322B00619DE9ADE6FFFF|

# Set XBE header media type
SM|*.xbe|C00001FF|
# All game regions
SR|*.xbe|00000007|

where can i get this fix? tried bloody near everything haha

The fix is in his post. Copy all of the text there starting at the first # all the way to the bottom of the post.
Paste that into a new text document and save it. Then rename it to 48450004.acl and you are done.