Thats normal for dogs to be territorial around theyre things,I guess since its her cage,she didnt want to other dog near it.and since she is the only dog in the house,she will be territorial with her things,and its not a big deal.as long as she's not being overly aggressive,like snapping,and snarliing etc.
For the petting thing,it might be just jealousy(spll?),she didnt want the other dog to get attention from someone who is giving her attention.
Your not being a bad mommy!

Mabye try when the other dogs owner is petting her,and the other dog comes up,mabye take her away to let the other dog get patted on the head or whatever.Try not to let her keep the othe dog away from his owner...

Sorry if that was confusing..lol