DATA sharing problem for additional distros in a Win7 - LL2 dual boot system

[m654321]

I originally had a multiple boot system with the operating systems of 4 distros on sda (all based on ubuntu), while the swap area and shared DATA partition were on sdb.  This worked well.  I then decided to set (up on 2nd laptop a Win 7 - LL2 dual boot): again a separate shared DATA partition was set up to allow filesharing between Windows 7 & LL2. Again this is worked well,  binding both "My_Documents" in win7 and the Directories in  /home of LL2 to the separate /mnt/DATA partition. 

However I experienced a problem with binding two more ubuntu-based distros on sda, in addition to the  LL2, and Win 7 on sda, to bind with /mnt/DATA on sdb. The two additional distros wont bind, though Win7 and LL2 remain successfully bound.

I have checked the "bind-home.conf" files that I created for the two additional distros but these look fine, as well as the /etc/fstab files that were set up.

When I try to mount /mnt/DATA, using the terminal, I get the following message for either additional distro:


m-z9@z9-AsusX71Q:~$ sudo mount /dev/sdb1 /mnt/DATA
[sudo] password for m-z9:
Mount is denied because the NTFS volume is already exclusively opened.
The volume may be already mounted, or another software may use it which
could be identified for example by the help of the 'fuser' command.

Is the presence of Win7 making the binding exclusive, i.e. it will only allow one other distro to share /mnt/DATA with it? Wondered if anyone else had experienced this and if there is a way around it?  I have no experience of the fuser command and what this means. 

Many thanks in advance for any help with this.
Kind regards
Mike