this is useful when you virtualbox is complaining about VBOX_E_IPRT_ERROR when using an iso file to install a guest OS(Windows 7)

mkdir -p isos/mountp
cp udfimage.iso isos
cd isos
geteltorito udfimage.iso > boot.bin
mount -o loop -t auto udfimage.iso mountp
cp -r mountp udfimagecontents
cp boot.bin udfimagecontents
mkisofs -udf -b boot.bin -no-emul-boot -hide boot.bin -relaxed-filenames -joliet-long -D -o newimage.iso udfimagecontents

reference: http://poppleit.com/how-to-edit-windows-7-install-dvd-extract-boot-image-and-create-iso-04-04-2011/