I have the same problem.
I am stuck at step 3... I tried almost all the ways.
1. tried "guess map"
2. changed the make of the pen drive(4GB) San disk and Kingston
3. Tried 3 different laptops.
4. tried GNOME 32 BIT and 64 BIT.
5.tried different types of layouts too.
Right now trying a 32 BIT version on a 16 GB pen drive.
Does Default allocation Unit size matter?
The target machine is :
ASUS 1015 PEM, (a netbook with a gig RAM)
Could someone help us here.