whos online ip format
 

I have Vbulletin 3.8.3 installed along with the vb blogs and VBSEO mod installed as well as the following mods from vbulletin.org:
AME 2.5 - Media Embedding for posts, sigs, vm's, groups and blogs
vBSEO Google/Yahoo Sitemap Generator
[AJAX] Post Thank You Hack
WebTemplates 3.7.x: VB Integrated CMS (Content Management System)
vMail - Verify Mail before registration
Cyb - Advanced Forum Rules
Cyb - Advanced Permissions Based on Post Count
microBUSINESS (Business directory and more)
Welcome Thread Upon Registration
Multiple account login detector (AE Detector)
Force Users to Read a Thread
Quick Editor Improver - Support Attachment
Blog Comments vBAdvanced CMPS
Multiple Options in Custom BBCode

My problem is that, in the who's online page (online.php) all the IPs are prefixed with a :ffff:
sample : ::ffff:86.173.2 , ::ffff:115.132
And I suspect it is due to this, that Rating posts, threads or blog entries is not possible as it always says the IPaddress is missing or invalid.

Does anyone know why this is happening and how to fix it ?
Site is running on lighttpd with php5 in fast-cgi mode.

Try disabling your modifications completely and then turn them on one-by-one (and making a post after you turn on each?) until the error occurs (check the IP of the post after you make it), then you will know which mod is causing the problem.