An attacker can run arbitrary code on the remote computer. This is because the remote IIS server is running a version of ActivePerl prior to 220.127.116.110 and has the Check that file exists option disabled for the perlIS.dll.
Either upgrade to a version of ActivePerl more recent than 18.104.22.1689 or enable the Check that file exists option. To enable this option, open up the IIS MMC, right click on a (virtual) directory in your web server, choose Properties, click on the Configuration... button, highlight the .plx item, click Edit, and then check Check that file exists. More Information: http://www.securityfocus.com/bid/3526