I was coding a bus I had on my pc, to obtain some coding skills again. I finished off the coding, and was attempting to encode this thing, but I keep getting the same errors

EDIT: Forgot to add info about it..
I'm using TTDPatch 2.5 rev 9, GRFcodec is up to date. I've created the bus using paint, saved it as a PNG, then opened up Irfanview and saved it as a .PCX. Usually, it's automatically saved as a 8 bit image, but this time it wasn't as you can see. I tried converting it to 8 bit in Irfanview, which resulted in the last lines..