Alain,
PlanetPress only make calls to the Perl executable and will never attempt to modify it.
If a server crash happened while the Perl.exe executable was running, it could have interrupted it's running process and could have left it corrupted, though this type of errors could have happened to any softwares, so it's not necessarely specific to PlanetPress. At this point, it seems like Perl will have to be reinstalled.
Also, have you scanned your machine for malwares such as viruses? Some of them could have corrupted executables on your system, so it would be a good idea to do a scan.
Regards,
Rapha