I downloaded and installed PP version 8.0.8 alpha 2, it is just great!
Everything went pretty good until I added a link to one of the projects.
Now PP won't let me log in:
I get the following error:
Error reported ()
Checking for duplicates
[id] => 764
[file] => C:\xampp\htdocs\PP088\application\plugins\links\models\ProjectLink.class.php
[line] => 245
[message] => Call to a member function getId() on a non-object
[explain] =>
[created] => 2011-10-10 09:18:14
[phpversion] => 5.3.8
[request] => /PP088/index.php?c=dashboard&a=index&1318238286
[browser] => Mozilla/5.0 (Windows NT 6.0; rv:7.0.1) Gecko/20100101 Firefox/7.0.1
[release] => pp088
[table_prefix] => pp088_
[phpinfo] => phpinfo()
PHP Version 5.3.8
Any idea on how to fix this?

This worked for me:
download the file unzip into the applications/plugins/links/models/ and it worked
after that for me.

I've had problem loading page when link module is enabled, link in overview and no selected project. Rewriting lines in method below helped (application\plugins\links\models\ProjectLink.class.php):

function getObjectUrl() {
return get_url('links', 'index', array('active_project' => $this->getProjectId()));
} // getObjectUrl

I'm not really sure, if this is clear fix, but worked for me:).