$ sudo dpkg --configure -a
Setting up freenx (0.4.4+0.4.5-4ubuntu3) ...
Use of uninitialized value in join or string at /usr/share/perl5/Debconf/DbDriver/Stack.pm line 104, <GEN1> line 2.
Use of uninitialized value in substitution (s///) at /usr/share/perl5/Debconf/Format/822.pm line 83, <GEN6> line 2.
Use of uninitialized value in concatenation (.) or string at /usr/share/perl5/Debconf/Format/822.pm line 84, <GEN6> line 2.
dpkg: error processing freenx (--configure):
 subprocess post-installation script returned error exit status 4
Errors were encountered while processing:
 freenx