Looks like you received a video in one of your groups that I don't know why it caused a corruption in the logs.

So every time you start up Yappari it reads the last line of every log for every open chat/group you have to show it in the main window and that's when the problem seems to appear.

I don't think any other way but to delete all the logs. You WILL lose all your contacts' history since I don't know exactly what log causes the problem.

So what you have to do is quit Yappari completely (no blue icon in the systray) and type from terminal:

rm -vrf /home/user/.yappari

CHECK BEFORE YOU PRESS ENTER THAT YOU TYPED EXACTLY THAT SINCE THAT COMMAND IS VERY DANGEROUS.

It will show you everything that was deleted and then start Yappari and it should work. Select Sync Now immediately after log in.

If you're totally against losing your history and you think you're up to it, you could try delete just the groups history with a command like this:

rm -vrf /home/user/.yappari/logs/*-*
rm -v /home/user/.yappari/roster.db
rm -v /home/user/.yappari/chats.db

and that should also work.

EDIT: The -v option was added to rm so you won't tell me "nothing happened" again.