use strict; 
my $drive;
my $count = -1;
open( LIST, "tpconfig -l|" ) or die $!;
while( <LIST> ) # I added the <LIST>... which I suspect you had.
{
    ($drive) = unpack '@0 A8',$_;
    ++$count if m/^drive/;
    system("tpconfig -delete -drive -index ${count}");
    # You should check all system calls for error.
    # system will set $? to an error code for you.
}
[download]

Update: You can read up on $? here

Another Update: raj8 says the script deletes the drives, but still generates the errors.
The "problem" is that system doesn't capture STDERR. The way to circumvent this is to redirect to nul: BUT BEWARE! This will hide ALL error messages from the system call!
Try this:

system("tpconfig -delete -drive -index ${count} 2>nul:");
die "Unknown Error with tpconfig $count" if $? >> 8;
[download]

Correct--this index 0 is hard to crack... Here is the output of $count:

1
1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
[download]

formatting tips

That said, edit the post, and I'd be happy to look at it again...

Monks, After total defeat, I come asking for assistance to this in my view (which is probably simple) difficult problem. I am attempting to grab the output of a system command, and based on the output, I am attempting to execute a system command on that output. I am attempting to increment the output and delete the drives based on that output. I will show an example of the output of the system command and the code. Third, I will list the errors associated from the code. Thanks--

C:\scripts\NT>tpconfig -l
Device Robot Drive       Robot                    Drive      Device
Type     Num Index  Type DrNum Status  Comment    Name       Path
robot      0    -    TLD    -       -  -          -          \\.\Scsi6
+:
  drive    -    0    dlt    1      UP  -          Drive0-1   \\.\Tape0
  drive    -    1    dlt    2      UP  -          Drive0-2   \\.\Tape1
  drive    -    2    dlt    3      UP  -          Drive0-3   \\.\Tape2
  drive    -    3    dlt    4      UP  -          Drive0-4   \\.\Tape3
  drive    -    4    dlt    5      UP  -          Drive0-5   \\.\Tape4
  drive    -    5    dlt    6      UP  -          Drive0-6   \\.\Tape5
  drive    -    6    dlt    7      UP  -          Drive0-7   \\.\Tape6
  drive    -    7    dlt    8      UP  -          Drive0-8   \\.\Tape7
  drive    -    8    dlt    9      UP  -          Drive0-9   \\.\Tape8
  drive    -    9    dlt   10      UP  -          Drive0-10  \\.\Tape9
  drive    -   10    dlt   11      UP  -          Drive0-11  \\.\Tape1
+0
  drive    -   11    dlt   12      UP  -          Drive0-12  \\.\Tape1
+1
  drive    -   12    dlt   13      UP  -          Drive0-13  \\.\Tape1
+2
  drive    -   13    dlt   14      UP  -          Drive0-14  \\.\Tape1
+3
  drive    -   14    dlt   15      UP  -          Drive0-15  \\.\Tape1
+4
  drive    -   15    dlt   16      UP  -          Drive0-16  \\.\Tape1
+5
robot      1    -    TLD    -       -  -          -          \\.\Scsi7
+:
  drive    -   16    dlt   17      UP  -          Drive1-0   \\.\Tape1
+6
  drive    -   17    dlt   18      UP  -          Drive1-1   \\.\Tape1
+7
  drive    -   18    dlt   19      UP  -          Drive1-2   \\.\Tape1
+8
  drive    -   19    dlt   20      UP  -          Drive1-3   \\.\Tape1
+9
  drive    -   20    dlt   21      UP  -          Drive1-4   \\.\Tape2
+0
  drive    -   21    dlt   22      UP  -          Drive1-5   \\.\Tape2
+1
  drive    -   22    dlt   23      UP  -          Drive1-6   \\.\Tape2
+2
  drive    -   23    dlt   24      UP  -          Drive1-7   \\.\Tape2
+3
  drive    -   24    dlt   25      UP  -          Drive1-8   \\.\Tape2
+4
  drive    -   25    dlt   26      UP  -          Drive1-9   \\.\Tape2
+5
  drive    -   26    dlt   27      UP  -          Drive1-10  \\.\Tape2
+6
  drive    -   27    dlt   28      UP  -          Drive1-11  \\.\Tape2
+7
  drive    -   28    dlt   29      UP  -          Drive1-12  \\.\Tape2
+8
  drive    -   29    dlt   30      UP  -          Drive1-13  \\.\Tape2
+9
  drive    -   30    dlt   31      UP  -          Drive1-14  \\.\Tape3
+0
  drive    -   31    dlt   32      UP  -          Drive1-15  \\.\Tape3
+1

#### CODE #####

use strict; 
    my $drive;
    my $count = -1;
    open( LIST, "tpconfig -l|" ) or die $!;
    while(<LIST>) 
    {
        ($drive) = unpack '@0 A8',$_;
        ++$count if m/^drive/;
        system("tpconfig -delete -drive -index ${count}");
    }

####  ERRORS   #########

Cannot delete drive index 0
Cannot delete drive index 0
Cannot delete drive index 17
Cannot delete drive index 32
[download]

I think it's your ++$count that's the problem. The drive numbers are sequential, but you have lines that begin with 'robot'. You don't increment $count for these lines (good) but you do the system command (not so good). Perhaps you should skip out of the loop early if you run into a robot:

    next if /^robot/;
    $count++;
    system( ... );
[download]

Without having anything named 'tpconfig' on my system, I can't check the man page for error messages, but I would be surprised if it allowed you to delete a drive you'd just deleted. The numbers seem to be fairly close.

Update: Here's a more complete code segment that really ought to do it for you:

my $drive;
my $count = 0;
open( LIST, "tpconfig -l|" ) or die $!;
while(<LIST>) {
    ($drive) = unpack '@0 A8',$_;
    next unless /^drive/;
    (system("tpconfig -delete -drive -index ${count}") == 0) or print 
+"Error deleting: $?";
    $count++;
}
[download]

Starts at 0, doesn't execute the command unless it's found a drive. Increments the number after it executes the command, checks $? for errors. (I'm not 100% certain about the syntax of that system checking, but it was in perlfunc that way.)