Fat32 formatted disk partitions do not mount

MacBook Pro: OS X 10.7.2

I have several flash drives and none of the partitions formated as FAT32 will mount. I have used the Disk Utility to erase and reformat the flash drives as FAT. After formatting the flash drive partition, the partition does not mount. The disk utility log file has the following message:

2011-11-25 15:16:55 -0600: Preparing to erase : “1GB”

2011-11-25 15:16:55 -0600: Partition Scheme: Master Boot Record

2011-11-25 15:16:55 -0600: 1 volume will be erased

2011-11-25 15:16:55 -0600: Name : “1GB”

2011-11-25 15:16:55 -0600: Size : 1.03 GB

2011-11-25 15:16:55 -0600: File system : MS-DOS (FAT)

2011-11-25 15:16:55 -0600: Unmounting disk

2011-11-25 15:16:55 -0600: Erasing

2011-11-25 15:16:56 -0600: 512 bytes per physical sector

/dev/rdisk4s1: 2000024 sectors in 250003 FAT32 clusters (4096 bytes/cluster)

bps=512 spc=8 res=32 nft=2 mid=0xf8 spt=32 hds=128 hid=2 drv=0x80 bsec=2003966 bspf=1954 rdcl=2 infs=1 bkbs=6

2011-11-25 15:16:56 -0600: Mounting disk

2011-11-25 15:16:56 -0600: Could not mount disk4s1 with name 1GB after erase

My external HD that I use for time machine backups has 2 partitions on it. One partition is FAT32 for transferring data between Mac and PC. The FAT32 partition on that drive does not mount either, although it used to mount. At least it used to mount prior to upgrading to Lion 10.7.2.

I am able to take the same flash drive with name 1GB and mount it on a MacBook running OS X 10.6.8.

Any ideas why FAT partitions will not mount