Your example doesn't match mine exactly. Try:

#!/usr/bin/perl

use strict;
use warnings;

my @args = ("glomosim", "data.in"); 
system(@args) == 0 or die "system @args failed: \n syscode:$? \n error
+:$! \n";
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ensure the location of glomosim is in your system PATH variable, or provide full paths to both the program and the input file. Also, you replied to yourself rather than anyone else. See the links I provided earlier.

I have put on the begining of .pl file :

use strict;
use warnings;
......
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I have a file with name (data.in) in the path (C:\glomosim\bin) which I want to execute it on cmd.exe using the command (glomosim data.in) where "glomosim" is a keyword to execute the file (glomosim is a NW simualtor). So I write the following :

  my @args = ("c:/glomosim/bin/","data.in"); 
            system(@args) == 0 or die "system @args failed: \n syscode
+:$? \n error:$! \n";
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then many errors appear :( ! Plz I need a help really!

A couple of things:

my @args = ("c:/glomosim/bin/","data.in");
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Here you provoide a directory, but not the name of the executable you want to call. Also if you have the data.in file within the bin directory you'll need to do:

my @args = ("c:\\glomosim\\bin\\glomosim.exe","c:\\glomosim\\bin\\data
+.in");
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Note that in both occasions I provide the full path to the file, and use \\ rather than / as the path separator. As a piece of general advice, the easiest way to get help with errors is to post the erros along with the code which generates them. How do I post a question effectively? has some great advice on posting. Let me know if you have further problems