Pear install problem

Hi all. I'm trying to install PHPDocumentor (www.phpdoc.org) and I'm
getting an error when using the pear install feature.

I've got the necessary files stored in /home/phpDocumentor-1.2.2 but
when I run pear install /home/phpDocumentor-1.2.2/package.xml I get the
following error:

Invalid checksum : 44835 calculated, 0 expected

I've been looking around on google but I haven't been able to find much
of any use.

Can anyone give me an idea as to what's causing this and how to fix it?

Cheers and TIA,

Pablo