Ok according to Kitt's guide for errors... it says the following:
- Rare error describing a 404... file was not found...
1) Your SD card is not formatted as FAT16 or FAT32 properly, reformat it.
2) You deleted the file, after you selected it for install
3) Appears there when there is no WAD folder on your device (SD card)
-You maybe missing the cIOS for that specific homebrew app to work
Hope that helps... This is from a list compiled by Kitt so don't think me if this helps!