This software is now FREEware you dont need to worry about registering it it will never shut off.
You probably went to their 3D site? - plus they no longer support the freeware after 2.0.0.23.
Here is the freeware link through my MediaFire account. (58.1 mb)
http://download950.mediafire.com/b74q33 ... 0.0.23.exe

After you install there are no available updates so the registration page here. (which used to be for paid registration updates)
file:///C:/Program%20Files/Right%20Hemisphere/Deep%20Paint/Resource/Register/dpreg.htm
Is no longer available (this link is in your deep paint menu), just in case you were wondering.

Here is a screen shot of Deep Paint:


To access the entire Deep Paint menu (and all your filters), go to Files/Pref/Directories and set up your ps filter directory.
Then open a new document or start one.
Or just open it in Gimp like i do now.

Any idea on how call gimp from xnview in linux ?

The XnView script works flawlessly. I was able to get Deep Paint (Thanks Rod), but the Deep Paint script doesn't work for me (the path has been corrected for my machine) and my Pixelitor script doesn't work for me either. Maybe it's a Windows 7 issue. I had to set Deep Paint to Windows XP compatability, for it to use PS filters. Not giving up, however!

Equally well it works Photobie 7.2.2 for Windows 7 /Vista / XP
http://www.photobie.com/download/download.php
and includes PS plugin manager !

in Windows there are many antagonist , but Xnview works very well also in linux (with wine that is a linux utility to run Windows programs )

Photobie interested me because it has a refresh feature added plug-ins - and what apparently can not get in Gimp.

http://registry.gimp.org/node/24977#comment-10535

xnview has a feature refresh plugin (a bit hidden : from the menu for PS filter you click "configure" from "configure" you may add new PS plugin folders that will be immediately loaded)

And if you want refresh because you added filters while xnview was running, you may just click "configure" and then in "configure mode just OK ,

That OK in configure refresh the PS filter list

@ RobA

i forgot to add before but the Xnview script has another advantage on PSPI:

you may NOT refresh PSPI, but no problem to refresh PS script in Xnview
to quote my reply in the Registry

Funny, my Xnview script stopped working.

If you added another script afterward, and they share certain variables or menu locations/names, the new one could confuse the one that did work.