(In reply to re: ABACADABrA (Solution)
Charlie: I used essentially the same program logic, and came to the same results (and probability) as you. After posting, I was puzzled when I read Jer's approach. Possibly he was reading the puzzle as reference to products (e.g. ABCD = A*B*C*D; AB=A*B, etc.) rather than as an alphameric of sorts, where each letter stands for a digit within a 2- or 4-digit number. The final "Note" could perhaps be read either way, but for me the references to 1111 and 9999 clearly favored considering these as 4-digit numbers, not as products.