Curiouser and curiouser!
Ok, with product enabled, error triggered.
Product disabled, error goes away but drop down still works!
In my product management, I've disabled your mod, simply because I didn't want to unisntall it should a fix come out. Thinking that disabling it would make it unusable (the clue is in the name!

) AND since the error went away, I thought all was good... Until I checked active topics and the + is still there and it is still clickable and it still shows the posts it was supposed to
So, I have an error that is intermittent not only for me, but for those that installed it, AND when disabled still runs!
You code hardcore mate!
Seriously though, ermm... What's the story? :P