"or can the pilot light not be lit because i cant see any flame in the little window in the front??"
I know absolutely nothing about your MPI 22 kerosene heater. But, I do know a tiny little bit about gas fired heating equipment like furnaces, boilers and hot water heaters.
The way to understand the gas valve, whether it be a gas valve on a natural gas fired water heater, furnace, or boiler, or a kerosene gas valve on a kerosene fired space heater is that the valve consists of two separate valves connected in series. That is, one valve is downstream of the other valve, so that the first valve has to be open before fuel can flow through it to the second valve.
The first valve in the series is typically called the "safety" or "safety valve". Gas ( or kerosene) has to flow through this safety valve before it can get to the second valve that controls flow to the main burner trays of the heater.
That safety valve is an electromagnetic valve, and it's held open by voltage produced by the thermocouple or thermopile sitting in the pilot light flame. As long as the pilot light heats the thermocouple or thermopile to produce sufficient voltage to keep that safety valve open, the heater knows that the gas flowing through that safety valve is burning and not accumulating in the room to eventually cause a gas explosion.
That is, as long as the thermocouple or thermopile is in the pilot light flame, it should get hot enough to produce sufficient voltage to energize that "safety" electromagnetic valve, and keep it open, thereby providing a continuous flow of fuel to the pilot light.
And, when you turn the heater on, or it's own thermostat senses that it needs to come on to heat up the room, gas or kerosene can then flow through the safety valve to the main gas valve, which also opens to allows gas or kerosene to flow to the main burner trays (where the pilot light ignites that gas or kerosene) to get the main burner trays burning.
(big but there)
It's normal for the thermocouple or thermopile in the pilot light to gradually produce less and less voltage as the thermocouple or thermopile gets older. Once it gets so old that the voltage produced by the thermocouple or thermopile isn't sufficient to keep that safety valve open, the pilot light goes out and the heater won't work anymore.
That's because if there's insufficient voltage produced by the thermocouple or thermopile, the safety valve closes, and with the safety valve closed, gas or kerosene can't flow through the safety valve to the main valve and then on to the burner trays. It can't even flow through the safety valve to the pilot light. So, even though you might turn the heater on, or even if it's own thermostat is telling it to turn on, as long as the safety valve is closed, no fuel can flow to the pilot light or through the main valve to the burner trays.
You normally need to replace the thermocouple or thermopile so that they generate sufficient voltage to keep that safety valve open. With the safety valve open, gas can flow through it and on to the burner trays, thereby allowing your heater to operate properly.
So, if you're not seeing a pilot light in the sight glass of this heater, then your pilot light appears to be going out, and that's normally because the thermocouple of thermopile that sits inside the pilot light flame needs to be replaced.
Get the manufacturer's 1-800 customer service phone number and confirm that your heater uses a thermocouple or thermopile sitting in the pilot light flame to generate the voltage needed to keep the safety valve open. If so, then you'll need to get a new thermocouple or thermopile to fix your heater. Confirm that's the probable cause of your pilot light going out with Customer Service. Find out where to order a new thermocouple or thermopile to install in your heater.
Now, just for your info...
A thermocouple or thermopile is simply a device that produces voltage when placed in a hot environment, like a flame. Each piece of natural gas or propane or kerosene fired heating equipment will have either a thermocouple or a thermopile sitting in it's pilot light, never both. Basically, all the thermocouples you're likely to come across produce about the same 22 millivolts and all the thermopiles you're likely to come across produce about the same 1.2 volts. So, you can use a longer thermocouple or a longer thermopile if one is available, but you can't use a shorter one if it's not long enough to reach from the pilot light flame to the gas valve.
Replacing the thermocouple or thermopile is a simple matter of either pulling it straight out of it's holder or unscrewing it from it's holder. It unscrews the same way as a light bulb; counter clockwise.
If you don't see a pilot light flame in the sight glass of your heater when it's not "ON" and actively heating your room, then your pilot light is out, and the usual cause for that is that the thermocouple or thermopile that sits inside the pilot light flame is too old and needs to be replaced.
Hope this helps.
If it's a bad thermocouple or thermopile, your 7 year old couldn't have caused the problem even if he wanted to. It's normal for thermocouples and thermopiles to lose voltage as they get older, and this is what keeps heating contractors busy every autumn until about November. They're just running around from house to house replacing old thermocouples or thermopiles so that furnaces and boilers work properly again.
PS: A thermocouple is simply two different kinds of metal connected together. When you heat that connection, the thermocouple produces a tiny voltage of about 22 millivolts DC. A thermopile is nothing more than a whole bunch of thermocouples connected in series. When you heat a thermopile, it just creates a whole bunch of voltage increases all connected in series, thereby generating a much larger voltage than a thermocouple could, or about 1.2 volts DC.
Furnaces and boilers tend to use thermocouples because they have a separate 24 VAC transformer to provide power to open the "main" valve inside the gas valve. Hot water heaters, especially commercial hot water heaters, tend to use thermopiles that generate more voltage because they don't have 24 VAC power available to them and so they use the power generated by the thermopile to operate BOTH the safety and main electromagnetic valves inside the gas valve.