Your arrays @values2 and @val2 and the scalar $val are never used, so let's remove them for now.

The main problem is that your assignment to zero is almost certainly not doing what you want. It is setting @values1 to (0) and @val1 to undef. When the "if" expression is false, those values are not changed and so what you are attempting to print is undefined - hence the warning. To illustrate, try changing your loop like this:

while (<CMD>) {
    my (@values1) = ('Not set', 'Really not set');
    my (@val1)    = ('Nothing here', 'Nor here');

# Nothing changed below here
    if ( $_ =~ /PING/ ){
         @values1 = split ;
    
            @val1 = split(/\(/,$values1[3]);
           $val1[1] =~ s/\)//;
             
      }  
    print "$values1[1] \n";
    print "$val1[0] \n";
}
[download]

I would also very strongly urge you to get into the habit of choosing meaningful names for your variables. @values1, @val1, @values2, @val2 and $val are all very similar and equally meaningless and this really adds to the confusion of the code.

Good luck.