windows ntfs Partitions become read-only

I have installed Ubuntu 11.10 in my system. but I can't write data into other partitions of the HDD, which are NTFS. how to gain read-write access to them??
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my fstab file contain this:

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc nodev,noexec,nosuid 0 0
# / was on /dev/sda9 during installation
UUID=d5c57cec-17e5-4ed6-8a3d-47271045522f / ext4 errors=remount-ro 0 1
# /home was on /dev/sda10 during installation
UUID=3604b8a1-902c-47a9-a799-96b8401d7950 /home ext4 defaults 0 2
# swap was on /dev/sda8 during installation
#UUID=c7acd495-ba23-429a-8438-42e0ad03e0cb none swap sw 0 0
/dev/mapper/cryptswap1 none swap sw 0 0

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output of fdisk -l is :
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incredible@atulz-Inspiron-N5010:/$ sudo fdisk -l

Disk /dev/sda: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000080

   Device Boot Start End Blocks Id System
/dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT
/dev/sda2 206848 65527807 32660480 7 HPFS/NTFS/exFAT
/dev/sda3 65529854 625121279 279795713 f W95 Ext'd (LBA)
/dev/sda5 126961758 270325754 71681998+ 7 HPFS/NTFS/exFAT
/dev/sda6 270325818 413689814 71681998+ 7 HPFS/NTFS/exFAT
/dev/sda7 413689878 625121279 105715701 7 HPFS/NTFS/exFAT
/dev/sda8 65529856 68458495 1464320 82 Linux swap / Solaris
/dev/sda9 68460544 88459263 9999360 83 Linux
/dev/sda10 88461312 126961663 19250176 83 Linux

Partition table entries are not in disk order

Disk /dev/sdb: 8166 MB, 8166703104 bytes
256 heads, 63 sectors/track, 989 cylinders, total 15950592 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xc3072e18

   Device Boot Start End Blocks Id System
/dev/sdb1 * 10680 15950591 7969956 b W95 FAT32

Disk /dev/mapper/cryptswap1: 1499 MB, 1499463680 bytes
255 heads, 63 sectors/track, 182 cylinders, total 2928640 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xa5b2fbf1

Disk /dev/mapper/cryptswap1 doesn't contain a valid partition table
incredible@atulz-Inspiron-N5010:/$