Hallo Harnam,

thank you for converting the schematic file!

As Erik already stated, for a normal 'C51' current into Port 0 pins is a little bit high.
Assume voltage drop accross LED is 1.6V...1.9V (depends on crystal mixture) then about (5V-1.8V) / 330Ohm = 10mA is flowing per Port pin. For many 'C51' derivatives maximum IOL per Port pin is 15mA and maximum IOL per 8-bit Port is only 26mA! So, with 330Ohms 80mA per 8-bit Port is flowing, which seems to be a bit too much.
You can proceed in 2 ways: Either decreasing resistors to 1k, which results in LED current of about 3.3mA, or to add an additional buffer. In the first case you probably will need to use then high efficient LEDs which give bright light with only 3.3mA. In the second case a 74HC541 could help. It accepts a total current through ground pin of 70mA, so that you have 8.75mA per LED.
Keep in mind that Port 0 outputs of many 'C51' derivatives will float when representing high state. So, when using additional 74HC541 you should connect a 10k pull-up array to Port 0 pins, like you have drawn it for Port 1 pins in your schematic.
Of course, another remedy could be the use of a 'C51' derivative, which can handle those 80mA.

Good luck,
Kai