Stuck bills in inventory are a bug from Seasons. I think they occur when a sim gives you a gift, but dies before you receive the gift. It can also happen when you come back from overseas - any gifts foreign sims gave you whilst away turn into bills (and sometimes omni plant seeds). You can mostly prevent this by checking your sims' mail regularly, including just before you come back from vacation, so you receive the gift in its proper form before the sim becomes unreachable and their gift turns into a fake bill. Mods such as MasterController can also be used to clean out stuck objects from your sims' inventory.
As for your first problem, I don't know why that would have occurred. World Adventures used to have a stack of bugs like that, but I was under the impression they've all been fixed through patches. Glad you sorted it out, though.