[PD] raspberry pi 3: moocow problem

[rolfm at dds.nl]

raspberry pi 3, raspbian jessie.
Pd 46.2 from raspbian repository.
compiled moocow.

in help-browser moocow is in the list.

but objects from moocow won't create in a blank patch.

clicking (through help-browser) on any2bytes-help.pd does create the 
object in the help-patch.
after this the creation of [any2bytes] works!!

putting a path to ~/pd-externals in preferences gives:
"duplicate lib"
"moocow is active"

putting moocow in startup preference doesn't help.

what is needed?

rolf