On a Windows 7 client I was getting the following error message after the VPN connection was completed and everything looked like normal. While the connection was completed (and the “lights” were green) the user could not do anything on the net. The log message on the client was repeating:
The data area passed to a system call is too small
In such cases it may help to check whether both sides have (or have not) comp-lzo set and set at the same value. In my case this was solved by setting:
comp-lzo no
at both the server and the client(s).
Managing organized complexity 
So I was just facing the same issue with my tun adapter not getting outside traffic and I saw that in the logs but thought to myself, “That’s proooobably not it.” and then I ran into this post. You are a gentleman and a scholar. Thanks for the easy fix. I feel stupid now. Android phone works now too!
It really fixed my problem, thank you so much!