Cannot delete the default string "My World". Can add characters after it though.
MCPE-5800
Naming Worlds
Resolved
Duplicate
1
(Unassigned)
Unconfirmed
Tablet - Android - Asus Nexus 7
0.8.0 beta build 2
Retrieved
similar experience for me, except that I could change the name and seed, but the 'DONE' button wouldn't work.
gt-i9000m - gingerbread 2.3