public abstract class AbstractPreparedStatement extends FBStatement
implements FirebirdPreparedStatement

The above line references FBStatement which according to the CVS
source at
http://cvs.sourceforge.net/viewcvs.py/firebird/client-java/src/main/org/firebirdsql/jdbc/
doesn't actually exist. There is a FirebirdStatement though. It is
also not in any of the referenced packages either.