I have had this issue as well.

Solution (xp fix) - Goto control panel and addremove programs. - You want to remove all the java components on your computer. - After uninstalling java go back to the ukmail site. - Goto printer configuration and it will prompt you to install java. - Let it install java. After this it should pick up your local printer.

Hope this helps for you as it did for me.

I checked for software updates for my Mac, there was a Java update in amongst others. After the software update, it seems to be OK now.