Base class package "HTML::Parser" is empty. (Perhaps you need to 'use' the module which defines that package first.)

If you are using TWIKI and you are receiving the following error message when you attempt to use the GUI to update or modify an entry:

====================================================================================
Base class package "HTML::Parser" is empty.
    (Perhaps you need to 'use' the module which defines that package first.)
====================================================================================


And the /opt/apache/htdocs/wiki/data/warn<date>.txt file shows the following:

====================================================================================
| 24 Mar 2010 - 15:22 | Base class package "HTML::Parser" is empty.
    (Perhaps you need to 'use' the module which defines that package first.)
 at /opt/apache/htdocs/wiki/lib/TWiki/Plugins/WysiwygPlugin/HTML2TML.pm line 41
BEGIN failed--compilation aborted at /opt/apache/htdocs/wiki/lib/TWiki/Plugins/WysiwygPlugin/HTML2TML.pm line 41.
        require TWiki/Plugins/WysiwygPlugin/HTML2TML.pm called at /opt/apache/htdocs/wiki/lib/TWiki/Plugins/WysiwygPlugin.pm line 194
====================================================================================

Then the issue could be that the HTML::Parser CPAN module is not installed, OR you are using the wrong perl.

for example. To verify whether or not you have the HTML::Parser perl module loaded you may do the following:

/usr/local/bin/perl -MHTML::Parser -e 0

If it completes without error, then you know it is loaded.

IF it completes w/o error, then you know /usr/local/bin/perl has it loaded. Repeat the same for /usr/bin/perl


/usr/bin/perl -MHTML::Parser -e 0

IF you find it provides an error, then that is the reason for the error. TWIKI uses /usr/bin/perl by default.

SOLUTION:

I recommend creating a soft link to /usr/;bin/perl TO /usr/local/bin/perl or re-compile /usr/bin/perl to contain the HTML::Parser CPAN extension.

After you verify the above command completes w/o error for /usr/bin/perl, then you should not receive the HTML::Parser error.