FYI
All working again on fully up to date F16 32b LXDE using:
Updating : 1:python-imgcreate-16.15-1.fc16.i686
1/6
Updating : lorax-16.4.9-1.fc16.i686
2/6
Updating : 1:livecd-tools-16.15-1.fc16.i686
3/6
...
98.75% done, estimate finish Fri May 4 23:08:43 2012
Total translation table size: 2048
Total rockridge attributes bytes: 2662
Total directory bytes: 8192
Path table size(bytes): 64
Max brk space used 1a000
308873 extents written (603 MB)
Inserting md5sum into iso image...
md5 = b6721c1b2a4075113f9eac059413c3b8
Inserting fragment md5sums into iso image...
fragmd5 = 6bef539478655131e88ffadb225871edd77f3912ec4d5f5db6dc3d2a791f
frags = 20
Setting supported flag to 0