Further to my whinge about date and time formats, this post on the MoneyWorks forum seems to have an answer. And it looks like it works.
In New Zealand, there is one more issue with Tiger. Apple still has not fixed the bug whereby setting your Region to New Zealand leaves you with U.S. settings for all WorldScript applications (like MoneyWorks).
In addition, just installing Tiger will reset your Worldscript date format to U.S. format.
You will need to change the Region to Australia, then log out and log back in to get correct date formatting in all applications. Having done that, you can then set the region back to New Zealand.