Dual Boot Xp and Vista

Hi i have gone through William tutorial and done exactly the same and got all the screen just like it shoud be but still i cnt load Xp!??Vista runs fine.(laptop acer aspire 5720z)

Error:
File: \ntldr
Status: 0xc000000f
Info: The selected entry could not be loaded because the application is missing or corrupt.

Any help will be much appreciated...