I see, thats very strange. Did you change something in your database, are you sure the adoptables species exists? I tried on my demo site, and didnt have your problem.

And btw, I think at this moment only private trade can be edited.

The only thing I can recall that I changed recently is in adopts.php I changed the adopts' default trade status to notfortrade instead of fortrade. Other than that I'm not sure, but I can check around and see if I changed anything else.

Ohh and that makes sense then, because I was trying to edit one of my public trades.

I see, anyway it doesnt make sense that an adoptable's trade status will lead to an adoptable species not found. Do you recall any other changes you made to the script? Did you change anything in the table adopts_adoptables?