Tried - same.  Aptitude complained that it can't reinstall because puredata is not installed.  So then installed.  dpkg grep search has this for puredata-core
/usr/bin (not sure why that comes up)
/usr/bin/puredata (is not there)
/usr/share/puredata (exists)
/usr/lib/puredata (folder exists but only contains 'doc, extra, po, tcl' folders)
/usr/lib/puredata/bin/pd & pd-watchdog (is not there)

'from which versions of pd did you upgrade? (it might be an upgrading problem)'
Unfortunately having tried so many options I can't be totally precise.  I tried apt-get via git and attempted to build from source.  Also the latest nightly builds of pd-extended, plus the debian repository version.  THis was a fresh install but as I said it still has the puredyne install on a separate partition with Pd.  I'm somewhat loath to remove it if I'm then going to have no working version of Pd.