I've just got the same error. It can be solved by adding one line to your nsd.tcl file.

#
# Tcl Configuration
#
ns_section ns/server/${server}/tcl
    ns_param   Library            /web/${server}/tcl
    ns_param   autoclose              on
    ns_param   debug                  false

# ----> Add this line pointing to your aolserver tcl-modules 
#       directory
    ns_param SharedLibrary /usr/local/aolserver/modules/tcl

The parameter SharedLibrary used to appear in openacs-3.2.5 sample nsd.tcl. Maybe the sample openacs-4-nsd.txt in file-storage should be updated or is that an effect of the new bootstrap?