dual boot - Parition problem on Ubuntu 18.04 LTS installation

Here is my 500 GiB drive, partition scheme:

As you can see there is one unallocated partition that I created beside dev/sda2 with 80 GiB volume. dev/sda2 contains Windows7 Home Edition and I'm trying install Ubuntu 18.04 LTS beside windows 7. I have problem with Ubuntu installation because Ubuntu not shown partitions correctly:

Note:

• when I start GParted I got this error:
  

  
  

  
  

  Libparted Error : Can't have overlaping partitions.

  
  




• # sudo fdisk -l /dev/sda:
  

  Disk /dev/sda: 465.8 GiB, 500107862016 bytes, 976773168 sectors
  Units: sectors of 1 * 512 = 512 bytes
  Sector size (logical/physical): 512 bytes / 4096 bytes
  I/O size (minimum/optimal): 4096 bytes / 4096 bytes
  Disklabel type: dos
  Disk identifier: 0xa0eb5b3a
  Device     Boot     Start       End   Sectors    Size Id Type
  /dev/sda1  *         2048   2081086   2079039 1015.2M  7 HPFS/NTFS/exFAT
  /dev/sda2         2081094 206050096 203969003   97.3G  7 HPFS/NTFS/exFAT
  /dev/sda3       373828832 701510872 327682041  156.3G  7 HPFS/NTFS/exFAT
  /dev/sda4       206050097 976769071 770718975  367.5G  f W95 Ext'd (LBA)
  /dev/sda5       206050160 373828823 167778664     80G  7 HPFS/NTFS/exFAT
  /dev/sda6       701528064 976769071 275241008  131.3G  7 HPFS/NTFS/exFAT
  Partition 2 does not start on physical sector boundary.
  Partition 4 does not start on physical sector boundary.
  Partition table entries are not in disk order.