Tim emailed me that this was a possible bug, and he's right....

"I noticed that in mod/oublog/allposts.php that you call blocks_have_content($pageblocks, BLOCK_POS_LEFT without initialising pageblocks anywhere. Surely that can't work!?"

My feeling is that the easiest way to resolve this is just to remove the potential for a left-column on the allposts page. Its a cluttered page anyway, and adding blocks would make it worse. There's no UI (I don't think) for adding blocks anyway to this mod, so I'm not sure its worth supporting their display - its just a bit of code left over from when I started this page by copying view.php