I can see an immediate issue, you missed the bit about using the qt-version, that is not going to work with WinXP, you need the gtk version. The file(s) are still there in
www.gmic.eu, tucked away further than that earlier post. The last of the gtk 32 bit:
https://gmic.eu/files/windows/gmic_gimp ... _win32.zipGet rid of what you have done, unpack that,
(1) put the whole gmic_gimp_gtk folder in the 2.8 profiles plug-ins folder,
(2) add the file libunistring-2.dll,
(3) set the path in Edit -> Preferences -> Folders
(4) entry is bottom of Filters menu.
remember to click the little arrow to update the filters (should be 502)

I see the link to libunistring-2.dll has gone, there are others but to save the searching, the whole thing zipped
https://www.dropbox.com/s/jwkfthw2o8ia7 ... k.zip?dl=0 9 MB
If you really want to use the qt version, you need to upgrade the Windows OS.