Burning rectifier capacitor 220V input
C1, C2 and C3 are shown on the circuit as 105K and this likely means they are 1uF capacitors. Three in parallel and at 50Hz means an impedance of about 1061 ohms. This is the problem because from a 230V AC supply there will be a current taken of about 212 mA.

The 212mA is calculated very roughly by subtracting about 5V (zener and forward diode drops in bridge) from 230VAC and dividing by 1061 ohms.

This will flow thru R3 (rated at 100 ohms) and will dissipate a power of about 4.5 watts just in that resistor. Then, the resistor will die and go open circuit and no longer will 212mA flow but, the voltage across C4 will rise to something around peak mains voltage of over 300 volts - this will kill the 50 volt rated capacitor dead.

I believe C1-3 are far too high in value and you should try using 100nF capacitors.