After using for a while the pd "vanilla" version, I installed the "extended" one.
I'm under win xp sp2, and I have serious problems in loading libraries.
It seems that importing to the registry the settings that are into "pd-settings.reg" does not work.
In fact I try to load some patch examples from the rradical documentation, but I get "could not create" errors on rradical objects.
I looked inside pd-setting.reg and surprisingly rradical library is included...:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Pd]
"loadlib1"="Gem"
"loadlib2"="cyclone"
....
"loadlib19"="rradical"
....

Why this happens? Is there a solution (besides startup binary loading and file path settings)?