You should definitely upgrade to the most recent version; as has already been mentioned, Win32 ppm packages exist that can be used to do this. Before doing so, it would be a good idea to remove the old installation, including the mod_perl.so Apache module in the Apache2 modules subdirectory. If mod_perl is registered with your ppm utility, you can remove it from within the ppm shell; otherwise, see the discussion of the mod_perl 2 renaming to see which files need to be manually removed - unless you have some custom Apache modules, a good start to this would be to just remove Apache2.pm and mod_perl.pm in C:\Perl\site\lib, and also the Apache subdirectories under C:\Perl\site\lib and C:\Perl\site\lib\auto.