You should check what your file system is. You can do this as follows:
bcbc@16:14:50:~$ mount | grep ' / '
/dev/loop0 on / type ext4 (rw,errors=remount-ro)
If your file system shows up as
ext4 then you can use ext2read, but this is read-only access. If it's
ext3 then ext2read will still work, and others such as Explore2fs will likely work. The website for Explore2fs seems to indicate that it's read only access too.
I've used ext2read and it's known to work with Wubi when you have an
ext4 file system.
Alternatively, you should consider storing shared data on an
NTFS partition. This is much easier for sharing with Windows and allows read/write access from both Operating Systems. In addition, if the data is important then it's safer to install them directly to the
/host or another mounted partition, rather than storing them on a loop device (the Wubi virtual disk) that is a single file, and when corrupted can be lost (along with all data within it).
PS a bit of background... Wubi installs are supposed to be
ext4 only, but when Ubuntu 11.10 came out, Wubi added a new disk image install option (when
wubi.exe is used to install Ubuntu only, and with no ISO present), and these disk images were supposed to be
ext4, but they found out later they were
ext3. The idea is that they'll switch back to
ext4 when this bug is fixed; it looks like the plan is to do this for release 13.10.
But any Wubi installs from USB/DVD or with the ISO, including Xubuntu, Kubuntu, Lubuntu, Edubuntu etc. all use