After an excruciating half-hour phone conversation with an Aeroplan techie (who kept swearing in french under his breath), the problem has been resolved. The issue being that I had not entered an area code for my international phone number (Singapore has no area codes). The solution is to simply put the first number of your phone number as an area code.

Managed to get 2 J-class seats on SQ/OZ for SIN-ICN return at 30,000 miles each. Not a bad deal for a 6.5 hour flight in international business on 5-star airlines!