Hello World! 
Sorry if this post is not in the right category, but I didn't find anywhere to post about U3 version of avast!
I have had the same problem (error in language DLL not found).
NB: Is it possible to simply reinstall the u3lang.dll in its original location for the drive to work properly on the pc (i.e., by copying this file from another location, and reinstalling it in the location where the file has been originally lost, on the first pc)?