Nik - WHICH country did you try to issue this ticket in?

Even though the Star Alliance rules state that you can issue with any alliance carrier, most asian countries do not follow this rule. eg. Thailand and Singapore where the originating carrier must issue the ticket - mainly due to commission levels.

eg. If you're in SINGAPORE, and the originating carrier is SQ, you must issue with SQ's plate. That said, SQ gives ZERO commission on their tickets. Hence agents are reluctant to issue tickets on SQ but as the originating carrier is SQ, they don't have a choice.