Lubuntu prerelease live - No root file system is defined

[George DiceGeorge]

>From the live install disk I clicked Install,
then resized the last Lubuntu partition to half
so that theres free space for another more uptodate Lubuntu
(hoping the UK keyboard will work)

But it says:
[No root file system is defined
Please correct this from the partitioning menu]

Which i do not understand.
aaaarrrgggghhhh!

[george]