After searching and reading about similar problems on this and other forums, I'm still at a loss about how to proceed. Here are the details.

Installing Ubuntu NR 9.10 from USB, and have no trouble booting from USB on HP Mini 110-1125NR--even got WiFi working without much hassle. But when I attempted to overwrite the Mini's hard drive install of Windows 7 Starter with Ubuntu, I got an error whether I chose the automatic partitioning option or attempted to configure it manually. Here's what the installer is trying to do:

"The following partitions are going to be formatted:
partition #1 of SCSI1 (0,0,0) (sda) as ext4
partition #5 of SCSI1 (0,0,0) (sda) as swap"

It successfully formats partition #5 (swap space), but at 5% into formatting partition #1, I get the following error:

"Failed to create a file system
The ext4 file system in partition #1 of SCSI1 (0,0,0) (sda) failed."

Based on suggestions found in other threads, I've tried manually partitioning with GParted, but that results in an error as well:

--------------------------
GParted 0.4.5
Libparted 1.8.8.1.159-1e0e
Create Primary Partition #1 (ext4, 29.29 GiB) on /dev/sda 00:00:12 ( ERROR )

create empty partition 00:00:02 ( SUCCESS )

path: /dev/sda1
start: 63
end: 61432559
size: 61432497 (29.29 GiB)

set partition type on /dev/sda1 00:00:01 ( SUCCESS )

new partition type: ext4

create new ext4 file system 00:00:09 ( ERROR )

mkfs.ext4 -j -O extent -L "Ubuntu" /dev/sda1

Filesystem label=Ubuntu
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
1921360 inodes, 7679062 blocks
383953 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=0
235 block groups
32768 blocks per group, 32768 fragments per group
8176 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000

Writing inode tables: done
Creating journal (32768 blocks):
mke2fs 1.41.9 (22-Aug-2009)
ext2fs_check_if_mount: Input/output error while determining whether /dev/sda1 is mounted.
mkfs.ext4: Input/output error
while trying to create journal
--------------------------------

If I try erasing the hard drive in Disk Utility, I get this error:

"Error creating file system: helper exited with exit code 1: BLKRRPART ioctl failed for /dev/sda: Device or resource busy"

Partitioning in Disk Utility doesn't work either:

---------------------------
Error creating partition: helper exited with exit code 1: In part_add_partition: device_file=/dev/sda, start=0, size=160041885696, type=0x83
Entering MS-DOS parser (offset=0, size=160041885696)
MSDOS_MAGIC found
looking at part 0 (offset 0, size 0, type 0x00)
new part entry
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 = 0
got it
got disk
new partition
added partition start=32256 size=160039240704
Error: Error informing the kernel about modifications to partition /dev/sda1 -- Device or resource busy. This means Linux won't know about any changes you made to /dev/sda1 until you reboot -- so you shouldn't mount it or use it in any way before rebooting.
Warning: The kernel was unable to re-read the partition table on /dev/sda (Device or resource busy). This means Linux won't know anything about the modifications you made until you reboot. You should reboot your computer before doing anything with /dev/sda.
ped_disk_commit() failed
---------------------------

Any tips on how to fix this? Similar threads suggest that the hard drive might be bad, but I just got the Mini last month. The HD has less than 100 hours on it and is healthy according to the SMART test I ran.

And of course, the initial partition attempt wiped out Windows (no big loss), so the hard drive is essentially inaccessible until I figure out how to make a partition stick.

Sorry if this belongs in the Ubuntu subsection--I'm a Linux newb and new to this forum, so this seemed like the right place to post.

I would delete all partitions and try to format all HDD in ext3 and then in ext4 just to check where is the problem.
After this, I will check more things.
Try this, and tell us what happend.

Have you tried using no swap space , I have a eeepc 900A running archlinux and I have ext3 for sda1 and no swap space.

I can delete all partitions via Gparted, but when I try to format the HDD in ext3, I get a similar result as shown in the details of my original post--Gparted creates an empty partition, sets the partition type on /dev/sda1, then returns an error when trying to create ext3 file system. Here's what appears to me to be the relevant info in the details report.

"ext2fs_check_if_mount: Input/output error while determining whether /dev/sda1 is mounted.
mkfs.ext3: Input/output error while trying to create journal"

If Gparted can't tell if the HDD is mounted, why is it able to successfully create a swap partition but not an ext3 or ext4?

After that, I opened Disk Utility. All the useful options--mount, unmount,check file system--are greyed out. Only Erase is selectable, and it just leaves me with an HDD that is "unrecognized."

Back in Gparted, if I try to create a new msdos partition table, it returns an error. If I create a Mac partition table, it gets a little further:

File System: unknown
Size: 31.50 KiB
Flags:

Path: /dev/sda1
Status: Not mounted
Label:
UUID:

First Sector: 1
Last Sector: 63
Total Sectors: 63

Warning:
Unable to detect file system! Possible reasons are:
-The file system is damaged
-The file system is unknown to Gparted
-There is no file system available (unformatted)