齿轮测量实验报告:ghost问题？

为什么我进DOS启动ghost后，再选择克隆或者还原，就会弹出这一句消息：There is no volid sonrce drive to choose。
不管是哪个版本都存在这种情况，我现在用的是7.0
里央的设置是这样的：
span(Spanning) = N
autoname(AutoName) = N
crcignore(CRC Ignore) = N
fcr(Create CRC32) = N
f32(FAT32 Conversion) = N
f64(64K FAT Clusters) = N
fatlimit(FAT Limit) = N
sure(Sure) = N
fro(Force Cloning) = N
rb(Reboot) = N
fx(Exit to DOS) = N
defaultImg(Default) = Y
ia(Image All) = N
ib(Image Boot) = N
id(Image Disk) = N
defaultTape(Default) = Y
tapesafe(Tape Safe) = N
tapebuffered(Tape Buffered) = N
tapeunbuffered(Tape Unbuffered) = N
tapeeject(Tape Eject) = N
ffx(UseExtINT13) = N
fnx(DisableExtINT13) = N
ffi(DirectIDE) = N
fni(DisableDirectIDE) = N
ffs(DirectASPI/SCSI) = N
fns(DisableDirectASPI/SCSI) = N