This is actually fairly significant news, as it is Australia’s A-330 MRTT tanker is the airframe that won the US tanker competition. Stephen Trimble hhas the official reasons for the delay:

1. the mutual decision by EADS and RAAF to take the aircraft to the Paris air show;
2. the RAAF directed changes to the MRTT configuration following contract award which has served to extend the development and testing program (including modifications to the refueling and avionics systems);
3. the RAAF has requested additional flight testing to ensure a more robust mission system when delivered.

If these are the all the reasons, then it really has no bearing on the viability of the airframe for the tanker competition, but I tend to be cynical on such things, so my guess is that EADS was finding it difficult to meet the schedule.

Additionally, Australia’s currency has generally been falling, which may create budget pressures that might lead them to defer purchases.

See also here.