Well, from what you are saying it seems that the simkit application is automatically enabled once the SIM card is inserted into the phone. That application does not represent any threat at all. It allows you to access certain functions from you mobile operator such as costs, information, weather, etc.
On the 2nd problem, it seems that you are using a WiFi connection and since you move away from the range of your connected networks, the phone disconnects then when you come back in range the phone connects to the networks. This is normal since you cannot broadcast your network to a very wide area.