Install 32-bit Sun Java 
sudo apt-get install ia32-sun-java6-bin 

Modify Wuala startup script 
gedit ~/wuala/wuala 

Change "java" to: 
/usr/lib/jvm/ia32-java-6-sun/bin/java 

Save 

Run Wuala 
~/wuala/wuala 

Voila!