Add Windows Vista to the grub menu

I had Windows Vista installed on my computer and created a partition to install Fedora 15. I chose the option to install fedora on any free space, so it should have installed on the empty partition. When I boot up, there are two boot options. Fedora and Other. When I select other, it gives an error:

BOOTMGR not found.

Is there a way to add Windows Vista to the Grub Bootloader by editing the grub menu. I don't know if it will help, but here is what I get when I run fdisk in the terminal:

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: 0x80000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1              63      321299      160618+  de  Dell Utility
/dev/sda2          321300    31776569    15727635    7  HPFS/NTFS/exFAT
/dev/sda3   *    31776570   583195897   275709664    7  HPFS/NTFS/exFAT
/dev/sda4       583196672   625141759    20972544    5  Extended
/dev/sda5       583198720   584222719      512000   83  Linux
/dev/sda6       584224768   625141759    20458496   8e  Linux LVM

Disk /dev/mapper/vg_mshfedora-lv_swap: 5301 MB, 5301600256 bytes
255 heads, 63 sectors/track, 644 cylinders, total 10354688 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: 0x00000000

Disk /dev/mapper/vg_mshfedora-lv_swap doesn't contain a valid partition table

Disk /dev/mapper/vg_mshfedora-lv_root: 15.6 GB, 15636365312 bytes
255 heads, 63 sectors/track, 1901 cylinders, total 30539776 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: 0x00000000

Disk /dev/mapper/vg_mshfedora-lv_root doesn't contain a valid partition table

The reason for your error message is the "Other" partition is missing the boot manager that Windows requires to start up. If you fix this then GRUB should be able to chain load the Windows partition. This question will help.