Questions About Upgrading to dependency based boot

[Mark Phillips <mark@phillipsmarketing.biz>]

I am running Debian testing on my computer. I am in the process of doing an apt-get update/apt-get dist-upgrade. 
 
I got this error message :
 
info: Checking if it is safe to convert to dependency based boot.
error: Unable to migrate to dependency based boot sequencing.
error: Problems detected: package bittorrent left obsolete init.d script behind, package dovecot-common removed but not purged, package modutils removed but not purged, package postfix removed but not purged, insserv: warning: script 'K90wparoamd' missing LSB tags and overrides,  insserv: warning: script 'K01nxsensor' missing LSB tags and overrides,  insserv: warning: script 'K01nxserver' missing LSB tags and overrides,  insserv: warning: script 'S25libdevmapper1.02' missing LSB tags and overrides,  insserv: warning: script 'libdevmapper1.02' missing LSB tags and overrides,  insserv: warning: script 'wparoamd' missing LSB tags and overrides,  insserv: warning: script 'nxsensor' missing LSB tags and overrides,  insserv: warning: script 'nxserver' missing LSB tags and overrides,  
grep: /var/lib/update-rc.d/*: No such file or directory

1. Can I resolve the first couple of problems with an apt-get purge bittorrent dovecot-common......?
 
2. What does the missing LSB tags and overrides mean? What should I do about them?
 
3. What is dependency based boot, and do I want it, need it? What do I do to get it to work correctly?
 
Thanks!
 
Mark