start your game then save your game with the save as option give it a new name( this way you will still have your original game) as your going to use some cheats here to see if someting hidden will show up like a spawner or the social jig which may be invisable in your case ( thats the oval thing i mentioned it's for two sims that interact with each other )
ctrl+shift+c ( hold all 3 together ) hit enter in the menu bar that appears at the top of the screen type in testingcheatsenabled true hit enter
again ctrl+shift+c type in buydebug on hit enter
again ctrl+shift+c type in moveObjects on hit enter
go to build/buy if it is a spawner you will see a box possiably with a circle or not depending on the spawner then hold shift click on the box if it says cannot delete then just grab it and move it to the garden or somewhere you can find it easy then go back to live mode hold shift click on the object option delete it
if it is the social jig then hopefully buydebug will make it show up then hold shift click on the object option delete it
turn the cheats of in reverse order
ctrl+shift+c ( hold all 3 together ) hit enter in the menu bar that appears at the top of the screen type in testingcheatsenabled false hit enter
again ctrl+shift+c type in buydebug off hit enter
again ctrl+shift+c type in moveObjects off hit enter
if a spawner or the jig is your issues problem solved again save your game with a save as new name to have a new fresh save delete the other new save as you won't need it
link to see the social jigs http://forum.thesims3.com/jforum/posts/list/701765.page#11150478
if all else fails then have the sims move to new house