check the location of your plugins (take a look at the /usr/local/etc/mt-daapd.conf for the location)
i found that the location of the plugins changed btween 15xx and 1695; it used to be in /usr/local/share/mt-daapd/plugins but is now at /usr/local/lib/mt-daapd/plugins
if its the same problem as described, i reported that this might catch a few ppl out to Ron in a different thread