Let me know if you see any scope of enhancement

Let's suppose for a moment that this script is called with a value for the App_name parameter of ';rm -rf ~', what do you suppose would happen? That would be bad enough but who knows what other access you are opening up to the potential miscreants. There's no point going into great detail here about how to fix this since there are thousands of tutorials on the web (not least the section "Don't Let User Data Near the Shell" from Ovid's CGI course which you would do well to read). But, if this is an actual CGI script on an actual webserver, take it down right now before it lets all the hordes of bad guys in.

Other things which could use attention:

• You should use strict.
• You should use warnings.
• You should use taint mode as recommended by Ovid's course (and read the rest of perlsec while you're there).
• You should avoid loading modules which you don't use (Date::Calc, Scalar::Util, Time::Local).
• Heed the recommendation in the CGI documentation and avoid using the HTML-generating code.
• You assign values to some variables ($cmd, $result) but then never subsequently refer to them. This is best avoided.
• Don't use backticks if you aren't going to use STDOUT from the subprocess (see previous point about not using $result).
• Pay heed to the interpolation rules - the value of $cmd is probably not what you think.

If you can correct all of these concerns there is every chance that you will have solved your original problem as a consequence. Good luck.