I receive an error when installing RQDA on Windows 10. I had run RQDA successfully, then a package wouldn't load and I deleted and tried to reinstall RQDA with these instructions: http://rqda.r-forge.r-project.org/. Since then, I receive errors pointing towards RGtk2 and GTK+. I tried loading RQDA both using the newest and older versions of R and RStudio. I tried on 3 different Windows computers.
Here is the link that shows the RQDA package was recently archived: https://cran.r-project.org/web/packages/RQDA/index.html The archive points towards requiring gWidgets, so I made sure the library of gWidgets loads successfully, which it does, as does library(gWidgetsRGtk2). I also took care to install RTools4.0 for R 4.0.0 (https://cran.r-project.org/bin/windows/Rtools/).
I made sure GTK+ is on my PATH. (Path: %GTK_BASEPATH%\bin;) (GTK_PATH: C:\GTK).
I also tried loading RQDA and dependencies manually, but that's a never ending process.
Here is the error I receive:
Failed to load RGtk2 dynamic library, attempting to install it.
Please install GTK+ from http://ftp.gnome.org/pub/gnome/binaries/win64/gtk+/2.22/gtk+-bundle_2.22.1-20101229_win64.zip
If the package still does not load, please ensure that GTK+ is installed and that it is on your PATH environment variable
IN ANY CASE, RESTART R BEFORE TRYING TO LOAD THE PACKAGE AGAIN
Error in getOption("encoding") : Knotenstack-Überlauf
Zusätzlich: Warnmeldung:
Failed to load RGtk2 dynamic library, attempting to install it.
Please install GTK+ from http://ftp.gnome.org/pub/gnome/binaries/win64/gtk+/2.22/gtk+-bundle_2.22.1-20101229_win64.zip
If the package still does not load, please ensure that GTK+ is installed and that it is on your PATH environment variable
IN ANY CASE, RESTART R BEFORE TRYING TO LOAD THE PACKAGE AGAIN
Error: package or namespace load failed for 'RGtk2':
.onLoad in loadNamespace() für 'RGtk2' fehlgeschlagen, Details:
Aufruf: NULL
Fehler: Knotenstack-Überlauf
Fehler: Paket 'RGtk2' konnte nicht geladen werden
Zusätzlich: Warnmeldung:
Failed to load RGtk2 dynamic library, attempting to install it.
Ausführung angehalten
ERROR: lazy loading failed for package 'RQDA'
* removing 'C:/Users/haunschild/Documents/R/win-library/4.0/RQDA'
Warning in install.packages :
installation of package ‘RQDA_0.3-1.tar.gz’ had non-zero exit status
Trying to install RGtk2, I receive the following:
Error in inDL(x, as.logical(local), as.logical(now), ...) :
kann shared object 'C:/Users/haunschild/Documents/R/win-library/4.0/RGtk2/libs/x64/RGtk2.dll' nicht laden:
LoadLibrary failure: %1 ist keine zulässige Win32-Anwendung.
versuche URL 'http://ftp.gnome.org/pub/gnome/binaries/win64/gtk+/2.22/gtk+-bundle_2.22.1-20101229_win64.zip'
Content type 'application/zip' length 25830230 bytes (24.6 MB)
downloaded 24.6 MB
Learn more about GTK+ at http://www.gtk.org
If the package still does not load, please ensure that GTK+ is installed and that it is on your PATH environment variable
IN ANY CASE, RESTART R BEFORE TRYING TO LOAD THE PACKAGE AGAIN
Lade nötiges Paket: cairoDevice
Warnmeldungen:
1: Failed to load RGtk2 dynamic library, attempting to install it.
2: In dir.create(config_path, recursive = TRUE) :
'C:\Users\haunschild\Documents\R\win-library\4.0\RGtk2\gtk\x64\etc\gtk-2.0' existiert bereits
> detach("package:RGtk2", unload = TRUE)
Fehler: Paket ‘RGtk2’ wird von ‘gWidgetsRGtk2’ benötigt, wird deshalb nicht detached ("Is needed by gWidgetsRGTk2', is therefore not detached")
> library(RGtk2)
I also tried:
pkgFile <- "RQDA_0.3-1.tar.gz"
download.file(url = url, destfile = pkgFile)
# Install dependencies
install.packages(c("DBI","RSQLite","RGtk2","gWidgets","gWidgetsRGtk2"))
# Install package
install.packages(pkgs=pkgFile, type="source", repos=NULL)
# Delete package tarball
unlink(pkgFile)
An received the same RGTk2 error loop.
Any help would be greatly appreciated! Thanks!

We've been discussing this issue at : https://github.com/Ronggui/RQDA/issues/38 Some have reported success installing it and have given feedback on how to do it. Some contributors are working to port RQDA to gWidgets2. May be one of their solutions works for you. Good luck.
After I gave the answer above I tryed to install it my self and this was as far as I've got using RKWard 0.7.1b, on VM with MsWins10. https://rkward.kde.org/ with R 3.6.3 in RKWard library (I had RQDA working before. So I uninstalled RKWard and deleted the library directory on C:\Program Files): https://cran.r-project.org/bin/windows/base/old/3.6.3 and RTools35 https://cran.r-project.org/bin/windows/Rtools/history.html also installed.
Selected GTK+ Restarted RKWard Installing ""RQDA_0.3-1.tar.gz", type = "source"", gave me an error: "Failed to load RGtk2 dynamic library, attempting to install it". But by chance, I just saw the post by @JanMarvin and it worked!!!
Then I ran:
And then
And it worked!! If anyone could please refine it or give other suggestions as how to install it on MsWin, would be very much appreciated! Thanks to @sjewo and @JanMarvin for their hard work!! porting this package to R 4.