my drive is a 80GB usb external harddisk.
during scanning, error message prompted: "The request could not be performed because of an I/O device error."
then, 3 choices come out: Retry, Ignore, Cancel.
when i choosed Retry 2 to 3 times, it will stop and go back to main menu.

the log is quite large, 10MB.
so i just paste the beginning and the end of the file here.

Please help.
Thank you very much.

Log:
[2008-07-13 23:17:17] [INFO ] Recuva v1.16.333
[2008-07-13 23:17:17] [INFO ] System Info: MS Windows XP SP3, Intel Pentium 4 CPU 3.00GHz, 512MB RAM, WinFast PX6600 TD
[2008-07-13 23:17:20] [INFO ] No update available
[2008-07-13 23:17:55] [INFO ] Boot sector:
6akBQk9PVFdJWjAAAkAgAAIAAAAA+AAAPwD/AD8AAABm5FAJg0oAAAAAAAACAAAAAQAGAAAAAAAA

AAAAAAAAAIAAKZ/aeyogICAgICAgICAgIEZBVDMyICAgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAzwI7QvAB8+/yO2OsvDU5vbi1zeXN0ZW0gZGlz

aywgcHJlc3MgYW55IGtleS4uLgcAQk9PVFdJWiBTWVO+uX2stA6zB80QrITAdfWYzRbNGQAAVao=

[2008-07-13 23:17:57] [INFO ] Trying 0000
[2008-07-13 23:17:57] [INFO ] End trying 0000
[2008-07-13 23:17:57] [INFO ] looking for FAT entry
[2008-07-13 23:17:57] [INFO ] looking for FAT entry
[2008-07-13 23:17:57] [INFO ] Matched FAT entry
[2008-07-13 23:17:57] [INFO ] Trying D8FF
[2008-07-13 23:17:57] [ERROR] jpg error
[2008-07-13 23:17:57] [INFO ] End trying D8FF
[2008-07-13 23:17:57] [INFO ] looking for FAT entry
[2008-07-13 23:17:57] [INFO ] looking for FAT entry
[2008-07-13 23:17:57] [INFO ] looking for FAT entry
[2008-07-13 23:17:57] [INFO ] looking for FAT entry
[2008-07-13 23:17:57] [INFO ] looking for FAT entry
[2008-07-13 23:17:57] [INFO ] looking for FAT entry
[2008-07-13 23:17:57] [INFO ] looking for FAT entry
[2008-07-13 23:17:57] [INFO ] Trying 0000
[2008-07-13 23:17:57] [INFO ] End trying 0000
[2008-07-13 23:17:57] [INFO ] looking for FAT entry
[2008-07-13 23:17:57] [INFO ] looking for FAT entry
[2008-07-13 23:17:57] [INFO ] looking for FAT entry

......

[2008-07-13 23:52:08] [INFO ] looking for FAT entry
[2008-07-13 23:52:08] [INFO ] looking for FAT entry
[2008-07-13 23:52:08] [INFO ] looking for FAT entry
[2008-07-13 23:52:08] [INFO ] Trying D8FF
[2008-07-13 23:55:07] [ERROR] WinAPI exception: FileDriveImpl.cpp(140) : The request could not be performed because of an I/O device error. (0x0000045d)

[2008-07-13 23:55:07] [INFO ] End trying D8FF
[2008-07-13 23:55:07] [INFO ] looking for FAT entry
[2008-07-13 23:55:07] [INFO ] looking for FAT entry
[2008-07-13 23:55:07] [INFO ] looking for FAT entry
[2008-07-13 23:56:10] [ERROR] WinAPI exception: FileDriveImpl.cpp(140) : The request could not be performed because of an I/O device error. (0x0000045d)

Any clue?
Please help, thanks!