...and all the different computers I use!?

I've for a long time experienced problems browsing through bookings on the FF section when logged in to qantas.com. I always use the provided 'Back' buttons rather than those in the browser, and often they lead to white screens - 'This website has a programming error' etc.

Recently I was looking at a multi-city booking for next summer. After filling in the routes & dates I'd often have to go back and change a date in attempt to find a sale fare - I found that every second time I submitted the form I'd get the white screen as above.

Last night I was toying with the idea of last minute Xmas travel to the UK, but only if I could find FF seats. Selecting 'flexible with dates' so I could see all of December then by default shows me only economy availability. e.g. MEL - HKG shows nothing until 01 Jan. So I select the PE, Business & First check boxes and resubmit - it then shows me lots of days with J availability in December e.g. 18th, 19th, 20th December. If I hover over 19th December it shows 'Duration: 9h 10m - stop 0'. If I select it then hit 'Select Flight' I get:

'Trip from Melbourne to Hong Kong is not available on the 19 Dec. Alternative dates can be selected below.'

Same for any other date even the Y availability it originally showed me!

Other routes I looked at would show various classes available on a day but clicking through would show no options in some of those classes.

I'm really fed up of it. I know I could call up but with so many potential routes and I am flexible with stopovers it would be so much better to get some reliable information at least beforehand.