cant delete hard drive files for reinstall; error msg posted in 'explaination'

while deleting files from an external hard drive i caused a problem; msg i got was 'unclean shutdown dpkg'
I tried different things for the last few days. I finally got the system to load a user onto a hard drive from an
official live 11.04 cd. Couldn't get the 12.10 to do it.
now im trying to repartition my hard drive and i get this msg:

Error creating partition: helper exited with exit code 1: In part_add_partition: device_file=/dev/sda, start=32256, size=37375642186, type=0x83
Entering MS-DOS parser (offset=0, size=40007761920)
MSDOS_MAGIC found
looking at part 0 (offset 32256, size 40007729664, type 0x05)
Entering MS-DOS extended parser (offset=32256, size=40007729664)
readfrom = 32256
MSDOS_MAGIC found
Exiting MS-DOS extended parser
looking at part 1 (offset 0, size 0, type 0x00)
new part entry
looking at part 2 (offset 0, size 0, type 0x00)
new part entry
looking at part 3 (offset 0, size 0, type 0x00)
new part entry
Exiting MS-DOS parser
MSDOS partition table detected
containing partition table scheme = 1
got it
got disk
new partition
added partition start=64512 size=37375607808
committed to disk
Error doing BLKPG ioctl with BLKPG_ADD_PARTITION for partition 5 of size 64512 at offset 37375607808 on /dev/sda: Device or resource busy

i dont know how to fix it. there is nothing on the disk I need to save, but I can't get it to wipe.
right now i am able to run the system, but only from the flash drive.