Code:
festival_client: connect to server failed
SayText: Couldn't open socket to Festival
Could not read Language file: /home/linux/.xastir/config/language.sys!
Error in language file! Exiting...
Looks to me as if it requres a running festival server. This is easy:
get it with klik://festival and then then launch festival as a server with
Code:
~/.zAppRun ~/Desktop/festival*.cmg festival --server
Besides, it seems to look for a configuration file in ~/.xastir/config/language.sys - and here comes the catch: xastir seems to replace this file at every run with a symlink (and due to klik's relocate-patch, this fails). So you have to do manually:

Code:
# unpack cmg
/sbin/fsck.cramfs -x ~/Desktop/xastir ~/Desktop/xastir*.cmg

# create directory
mkdir -p ~/.xastir/config/share/xastir/config

# copy language files
cp ~/Desktop/xastir/usr/share/xastir/config/language-* ~/.xastir/config/share/xastir/config

# delete unpacked AppDir
rm -rf ~/Desktop/xastir/
Now it runs.

Greetings,
probono