The problem is when i try to read a file which is empty then it crashes (because the code try to read a file and it find nothing in the first line and code breaks with an error that couldnt open this file).

That makes no sense. If the file is empty the while loop will never be entered:

E:\test>dir
 Volume in drive E is New Volume
 Volume Serial Number is 1821-B83A

 Directory of E:\test

28/01/2015  08:10    <DIR>          .
28/01/2015  08:10    <DIR>          ..
28/01/2015  08:10                 0 fred
               1 File(s)              0 bytes
               2 Dir(s)  1,624,181,088,256 bytes free

E:\test>perl -E"while( <> ){ print 'got here'; }" fred
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BTW, this is also nonsense:

open my $fh, '<', 'C:\ppp.txt', or die "Could not open file $!";
     while (my $line = <$fh>) 
     {   foreach my $str ($line)
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Iterating a foreach over a single scalar variable, means it will only ever iterate once. Ie. it is completely redundant.