You may have to do it manually then.

I got the 5.006 zip file. You can extract it to your c:/unzipped/AdminMisc_5006 dir...then

copy from the bin dir the AdminMisc.dll to the <perldir>\site\lib\auto\Win32\AdminMisc\AdminMisc.DLL
copy the ADMINMSC.PM file to <perldir>\site\lib\Win32\AdminMisc.PM
copy for the test dir all the .pl files to <perldir>\site\lib\auto\Win32\AdminMisc\
copy the readme, Readme.pod, Win32-AdminMisc.ppd all to <perldir>\site\lib\auto\Win32\AdminMisc\
my ppm install then writes a .packlist in the <perldir>\site\lib\auto\Win32\AdminMisc\ dir which looks as follows

C:\Perl\site\lib\Win32\AdminMisc.PM
C:\Perl\site\lib\Win32\AdminMisc\DESKTOP.PL
C:\Perl\site\lib\Win32\AdminMisc\MEMGROUP.PL
C:\Perl\site\lib\Win32\AdminMisc\NewDesktop.pl
C:\Perl\site\lib\Win32\AdminMisc\README
C:\Perl\site\lib\Win32\AdminMisc\RUNAS.PL
C:\Perl\site\lib\Win32\AdminMisc\Readme.pod
C:\Perl\site\lib\Win32\AdminMisc\RenameUser.pl
C:\Perl\site\lib\Win32\AdminMisc\SCHED.PL
C:\Perl\site\lib\Win32\AdminMisc\SCHED2.PL
C:\Perl\site\lib\Win32\AdminMisc\SWITCH.PL
C:\Perl\site\lib\Win32\AdminMisc\Test.pl
C:\Perl\site\lib\Win32\AdminMisc\VALIDATE.PL
C:\Perl\site\lib\Win32\AdminMisc\Win32-AdminMisc.ppd
C:\Perl\site\lib\Win32\AdminMisc\listdesktop.pl
C:\Perl\site\lib\auto\Win32\AdminMisc\AdminMisc.DLL
[download]

I don't think this updates the ppm database of installed modules but maybe some-one more experienced can finish this off for me... or it may just work.

Hope this helps...