Hi here is the info that i gathered i Hope it helps:
03/21: You tube changes something that effected bulk video sharing and messaging ... never TTB never identified exactly what the change youtube did
to stop bulk video sharing/messages
03/21: Post from TTB user
Posted: Wednesday, March 21, 2012 8:20:44 PM
I am receiving the same error message for bulk video sharing. I checked the sent box but it appears that TTB did not send multiple messages to the same user. Can TTB staff please help us on this issue!!
TTB responds:
Posted: Thursday, March 22, 2012 1:07:22 AM
It's 1AM and I'm a bit delirious but the new version is out with a fix. Keep us posted. We test as much as we can but rely on users to let us know if they run into issues.
The release also includes something that I've been working on all week which involves converting everyone's account to their Channel name (instead of having some people log in with their email address)
TTB releases version 2.13.5.1
Date Released: Mar 22, 2012
I just checked the blog and the last user says it is still not fixed from TTB side
Posted: Friday, March 23, 2012 5:34:10 AM
he problem isn't fix, I have the same message now

Please help!
Now before this happened i was using not even the latest summer crack and everything was working great. 2.13.1.1

THANK YOU !!!
Also the message that pops up for the upgrade from TTB is as follows and the fix description:
(Thursday, March 22, 2012)
Version 2.13.5.0: Emergency fix for Messages/Share Video. Also, all Tube Toolbox accounts will be based on your Channel name (not email address).
(Thursday, March 22, 2012)
Version 2.13.5.1: Fixes for people who are required to log in with Google Email Address
Ok at least I Tried to fill in the info/history ...