1. Read the perldelta* manpages to find out the most important differences between perl versions.
2. Go through each error and see what it says. In most cases, it should be clear what does not work.

Here is one thing I've found:
"our" does not work. use "use var" instead

It is not too hard to examine each error and work the problem.

Keep in mind that since you are obviously using two distinct and different perl installations you may be missing needed modules. This would cause you "errors" but they would not likely be related to the different perl distributions. (Yes, there are *some* included modules in 5.6 that aren't in 5.005) To fix, go to cpan.org to 'fill up' on the needed modules.

You might consider upgrading your Perl installation. It's not as hard as you think.

use vars , not  use var. Example: use vars '$varname', '@varname'; instead of our $varname; our @varname;

Update: single-quote vars instead of double quote.

Watch yourself :)

use strict;
use warnings;
use vars "$varname", "@varname";
__END__
Possible unintended interpolation of @varname in string at - line 3.
Global symbol "$varname" requires explicit package name at - line 3.
Global symbol "@varname" requires explicit package name at - line 3.
BEGIN not safe after errors--compilation aborted at - line 3.
[download]

From perlhist:

          5.004_02      1997-Aug-07
          5.004_02_01   1997-Aug-12     aka perl5.004m3t1
          5.004_03-t2   1997-Aug-13     aka perl5.004m3t2
          5.004_03      1997-Sep-05
          5.004_04-t1   1997-Sep-19     aka perl5.004m4t1
          5.004_04-t2   1997-Sep-23     aka perl5.004m4t2
          5.004_04-t3   1997-Oct-10     aka perl5.004m4t3
          5.004_04-t4   1997-Oct-14     aka perl5.004m4t4
          5.004_04      1997-Oct-15
          5.004_04-m1   1998-Mar-04     (5.004m5t1) Maint. trials for 
+5.004_05.
[download]

I think I fixed most of the errors. Mostly by including the missing modules and going through each error. There are two more things I have to do: 1. I have to replace "confess" keyword with "die", because it compalined "Cannot use bareword "confess" when "strict subs" is in use". Can i get the module that Confess is present. 2. My current test scripts use Test.pm file which is not supported in v5.004. Do I need to rewrite the tests again?

confess comes from Carp, so you have to use Carp to get it.

Hi all, I think I fixed most of the errors. Mostly by including the missing modules and going through each error. There are two more things I have to do: 1. I have to replace "confess" keyword with "die", because it compalined "Cannot use bareword "confess" when "strict subs" is in use". Can i get the module that Confess is present. 2. My current test scripts use Test.pm file which is not supported in v5.004. Do I need to rewrite the tests again? -Sagar.