Konquerer isn't officially supported by Prototype.js which Rails uses for it's Ajax stuff.
The latest version of Prototype is compatible with the following browsers: Browser Version(s) Mozilla Firefox ≥ 1.5 Microsoft Internet Explorer ≥ 6.0 Apple Safari ≥ 2.0 Opera ≥ 9.25
There should be no issue with Safari 3 or 2.
After a couple of days of tearing my hair out I have solved the problem another way. I have ditched the use of the 'observe_field' helpers and written the routine from scratch in java script.
Now it works in all of these browsers.
If anyone else stumbles accross this thread, I was greatly helped by this howto:
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