E2028 Sets may have at most 256 elements (Object Pascal)
This error message appears when you try to declare a set type of more than 256 elements. More precisely, the ordinal values of the upper and lower bounds of the base type must be within the range 0..255.
program Produce; type BigSet = set of 1..256; (*<-- error message given here*) begin end.
In the example, BigSet really only has 256 elements, but is still illegal.
program Solve; type BigSet = set of 0..255; begin end.
We need to make sure the upper and lower bounds and in the range 0..255.