In order for xqbib to find your databases, you should be
sure to have the environment variable QDDBDIRS set appropriately.
For example, if all your Qddb BibTeX databases are in
~/databases/bibtex, then you would enter the following
command (bash shell syntax):
export QDDBDIRS=~databases/bibtex. You probably
also want to add this command to your ~/.bashrc
startup file.