Robbo, if you remember, I was waiting for you to have a look at that memory error (Your forum has gone now so I have no link to refer you to).
Using the current version, we experienced a problem with page navs, so you suggested I try build 28. I did, but editing or adding an ad was fine...until the forum had a few threads in which case the plugin died with a memory error.
I narrowed the problem down, it's within the Position model, particularly the foreach loop on lines 41-51
As we only use one position anyway at the moment, I commented out that loop and bingo.
Just an FYI