We recently installed Spreadsheet-WriteExcel-2.14 and started encountering errors in the Encode module (core dumps).
(we are running perl 5.8.0 and the Encode version is 1.83)
The complaint was that perl could not find Encode/ConfigLocal.pm. So I went looking for it in the perl lib directories but all I could find was ConfigLocal_PM.e2x. Looking at this file revealed...

> cat ConfigLocal_PM.e2x 
#
# Local demand-load module list
#
# You should not edit this file by hand!  use "enc2xs -C"
# 
package Encode::ConfigLocal;
our $VERSION = $_LocalVer_;

use strict;

$_ModLines_

1;
[download]

So I ran the enc2xs command and it built perl/lib/perl5/5.8.0/sun4-solaris/Encode/ConfigLocal.pm
Running perldoc enc2xs reveals...

enc2xs builds a Perl extension for use by Encode from either Unicode Character Mapping files (.ucm) or Tcl Encoding Files (.enc). Besides being used internally during the build process of the Encode module, you can use enc2xs to add your own encoding to perl. No knowledge of XS is necessary.

So I know what it does.
The question is, where is it documented that this needed to be done? I can't find it.

update:
I forgot to post the original errors. Here they are...

Can't locate Encode/ConfigLocal.pm in @INC (@INC contains: . /home/ora
+mwh/scripts /home/utils/perl/lib/perl5/5.8.0/sun4-solaris /home/utils
+/perl/lib/perl5/5.8.0 /home/utils/perl/lib/perl5/site_perl/5.8.0/sun4
+-solaris /home/utils/perl/lib/perl5/site_perl/5.8.0 /home/utils/perl/
+lib/perl5/site_perl) at /home/utils/perl/lib/perl5/5.8.0/sun4-solaris
+/Encode.pm line 52. 
Can't use an undefined value as a HASH reference at /home/utils/perl/l
+ib/perl5/site_perl/5.8.0/Spreadsheet/WriteExcel/Workbook.pm line 771 
+during global destruction.
[download]