pgadmin debug on windows

Hello,

I've installed on a windows xp machine beta 1 of postgresql 8.3 and pgadmin III 1.8.
I've loaded a backup of a database from a 8.2.5 machine, for testing purpose, and tried
the new functionality of plpgsql debug of functions.

But I was disappointed to see that does not work.
I try to debug right clicking on a function (very basic function indeed)
and choosing debug->debug from the contextual menu, but what I obtain is
"an unhandled exception occurred." and Abort/Retry/Ignore buttons. Same if I try to set breakpoint
(i can see the debug window this way, but completely empty)
Sorry I cannot give more details, but I don't have them myself <g>

Can someone give me an idea of what's wrong? Is maybe debugging not yet available in this beta release
of postgresql on windows??? Or the problem is that the function is imported from a 8.2.5 database?

Thanks everyone.