Blank Page when configuring with JomSocial

Alright, we found it. On our test site with PHP 5.1 we hadn't installed JomSocial yet. When we did, WHAMO.

Anyone affected, please try the following and post your results. This fixed it immediately for us. It's a combination of both JomSocial and FBConnect check to see which version of PHP your using (and whether the JSON library needs to be included). However, they check in slightly different and conflicting ways.

In /administrator/components/com_jfbconnect/assets/facebook-api/jsonwrapper/jsonwrapper_inner.php on lines 4/5, add the following bolded line:
if (!defined('SERVICES_JSON_SLICE'))
require_once 'JSON/JSON.php'; # <--- this line should already be there

There is another post about another issue with this file below that we'd recommend implementing now as well (while your there):
<!-- m --><a class="postlink" href="www.cmsmarket.com/forum/index.php?f=38&t...&rb_v=viewtopic#p413">www.cmsmarket.com/forum/index.ph ... topic#p413

Please let us know how these 2 changes go. Both will be included in the upcoming 2.0.1 release.

This is caused when another component is including the Facebook libraries. We'll add a check in the future to not throw this error. I'm assuming this is because you've enabled Facebook Connect integration within JomSocial. I'd recommend only using one or the other, and not both, as they accomplish similar goals in very different ways.

Your issue is actually separate than the others in this post. There is an issue with the JFBCLogin module where it can't be displayed 2 times on the same page. To fix your issue, do one of the following:
1) Don't show more than once (obviously not optimal, do the next one)
2) Update the following line in /modules/mod_jfbclogin/mod_jfbclogin.php
Line 6, change "require" to "require_once":

require_once(dirname(__FILE__).DS.'helper.php');

We've added this to the module and will be posting an updated version shortly.