So I’m familiar with the Qantas “Multi-City” search tool.
But why is it when you search for ff availabiltiy a couple of months from now you can no longer see the usual calendar with reward availability any more?
Instead it comes up with “It looks like something went wrong there. Flights out are not available for the date/time specified. Modify your request and search again. (#9200)”
How I hate Qantas ff search engine… let me count the ways 
Hi Graham,
Let me know if I’m trying to teach you to suck eggs…
As far as I know it simply means there are no reward flights available for that route for the given dates you’re searching. This is a somewhat useful site for looking up the various error codes on Qantas’ website:
When I see this error, I change the search period (ie. the date range I’m looking at), skip forward to see the next 14 days, or try another route. Not exactly helpful advice to you really, I know.
Another thing I’ll often do is use the main Qantas search engine which shows both the cash price as well as which flight combo’s have rewards seat availability too. This helps narrow the search dates and routes down, and then I’ll go search via the Multi-City engine to try piece together my final itinerary. This has proved valuable sometimes, helping to get around odd error codes when using the Multi-City tool - such as flights that it thinks do have reward seats available, but then they don’t show up on the main search engine. If I can then find a replacement reward seat/date and then update the multi-city search, it “usually” then shows up and I can book through to completion.
I would have to agree with you though, the Qantas search engine is one of the THE most painful flight search tools around. I feel your pain! 
Thanks jenart!! Appreciated. That was it! In the past I’ve just been so used to seeing the calendar just pop up when I search different routes - showing reward availability over a month period. I obviously had just happened to enter date/s when there was no reward flight at all and that’s why that error came up. It just confused me because I kept stepping forward, day by day, and kept getting the same error.