$ ppm install Gtk3 Gtk3
Installing package 'Gtk3'...


Error installing package 'Gtk3': Error reading http://www.sisyphusion.
+tk/ppm/x86/Gtk3-516.tar.gz

Installing package 'Gtk3'...
Error installing package 'Gtk3': Could not locate a PPD file for packa
+ge Gtk3
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This went ok but it made no improvements to install Gtk3 timing out slowly at different points

 ppm install Crypt-SSLeay Net-SSLeay Mozilla::CA IO::Socket::SSL
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$ ppm install Gtk3 Gtk3

Does it make any difference if you instead run ppm install Gtk3
Are you running this in a bash shell ? I've never used ppm in anything other than the cmd.exe shell, but I'm not sure, off the top of my head, whether that should matter.
Also, what does perl -V output ?

I downloaded http://www.sisyphusion.tk/ppm/x86/Gtk3-516.tar.gz and it unpacked fine for me.
Also grabbed http://www.sisyphusion.tk/ppm/Gtk3.ppd which seems ok, too.

Cheers,
Rob

ppm install Gtk3 makes no difference, only the error message is usually about Gtk3-516.tar.gz, after really really long delay

I'm using cmd.exe

oh, PPM.log sometimes complains

ppm.bat: read_href: Error reading http://www.sisyphusion.tk/ppm/Glib-O
+bject-Introspection.ppd: 500 Can't connect to www.sisyphusion.tk:80 (
+A connection attempt failed because the connected party did not prope
+rly respond after a period of time, or established connection failed 
+because connected host has failed to respond.) at Sun Feb 23 17:54:30
+ 2020
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Summary of my perl5 (revision 5 version 16 subversion 1) configuration
+:
   
  Platform:
    osname=MSWin32, osvers=6.0, archname=MSWin32-x86-multi-thread
    uname=''
    config_args='undef'
    hint=recommended, useposix=true, d_sigaction=undef
    useithreads=define, usemultiplicity=define
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=und
+ef
    use64bitint=undef, use64bitall=undef, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='gcc', ccflags =' -s -O2 -DWIN32  -DPERL_RELOCATABLE_INCPUSH -D
+PERL_TEXTMODE_SCRIPTS -DUSE_SITECUSTOMIZE -DPERL_IMPLICIT_CONTEXT -DP
+ERL_IMPLICIT_SYS -fno-strict-aliasing -mms-bitfields -D_USE_32BIT_TIM
+E_T',
    optimize='-s -O2',
    cppflags='-DWIN32'
    ccversion='', gccversion='4.6.3', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=undef, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='long lo
+ng', lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='g++', ldflags ='-D_USE_32BIT_TIME_T -s -L"D:\perl\lib\CORE" -L
+"D:\perl\mingw\mingw32\i686-w64-mingw32\lib"'
    libpth=D:\perl\mingw\mingw32\i686-w64-mingw32\lib
    libs=-lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomdlg32 
+-ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_32 -l
+mpr -lwinmm -lversion -lodbc32 -lodbccp32 -lcomctl32
    perllibs=-lmoldname -lkernel32 -luser32 -lgdi32 -lwinspool -lcomdl
+g32 -ladvapi32 -lshell32 -lole32 -loleaut32 -lnetapi32 -luuid -lws2_3
+2 -lmpr -lwinmm -lversion -lodbc32 -lodbccp32 -lcomctl32
    libc=, so=dll, useshrplib=true, libperl=libperl516.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags='-mdll -D_USE_32BIT_TIME_T -s -L"D:\perl
+\lib\CORE" -L"D:\perl\mingw\mingw32\i686-w64-mingw32\lib"'


Characteristics of this binary (from libperl): 
  Compile-time options: HAS_TIMES HAVE_INTERP_INTERN MULTIPLICITY
                        PERLIO_LAYERS PERL_DONT_CREATE_GVSV
                        PERL_IMPLICIT_CONTEXT PERL_IMPLICIT_SYS
                        PERL_MALLOC_WRAP PERL_PRESERVE_IVUV
                        PERL_RELOCATABLE_INCPUSH PL_OP_SLAB_ALLOC
                        USE_ITHREADS USE_LARGE_FILES USE_LOCALE
                        USE_LOCALE_COLLATE USE_LOCALE_CTYPE
                        USE_LOCALE_NUMERIC USE_PERLIO USE_PERL_ATOF
                        USE_SITECUSTOMIZE
  Built under MSWin32
  Compiled at Oct 14 2012 15:01:37
  %ENV:
    PERL_MB_OPT=" --config installhtmldir=  --binhtml= "
  @INC:
    D:/perl/site/lib/MSWin32-x86-multi-thread
    D:/perl/site/lib
    D:/perl/vendor/lib
    D:/perl/lib
    .
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$ ppm version
11.11_04
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