1) is the cat burglar can burgle pets,potion or spells???

2) if a player land on another player can he use a follower ability and not attack they characte

1) It's right there on the card actually: "choose 1 Object". Therefore, you can burgle for potions - as they are objects - but you can not burgle for spells, pets or anything else that is not an object. (You can for scrolls, because they are objects that give you spells, mind.)

2) Not sure what you mean right here - a player can use a special abillity (if he/she has one) on another player he/she lands on instead of attacking. If you are referring to a special follower, give me the text please, so I can check it out.

The follower say that if you encounter another player you can take object from him, is this mean that it's all the encounter? Or he must attack me as we'll?

Hamal22 said:

There are some followers introduced in the City expansion that you can use on a character you land on. I consider this as a bad wording, as you don't land on characters, but this was the wording adopted from the beginning of 4th edition for abilities such as the Sorceress'.

Since the ability can be used when you land on a character, you can use the Follower ability and then decide to encounter the character (attacking or using a character's special ability) or encounter the space.