Given the previous example .obj file header:

####
#
# OBJ File Generated by Meshlab
#
####
# Object voronoi.obj
#
# Vertices: 763
# Faces: 88
#
####

The comment lines will be printed out instead of showing a warning message. For example:

DotobjModelLoad(): "###"
DotobjModelLoad(): ""
DotobjModelLoad(): "OBJ File Generated by Meshlab"
DotobjModelLoad(): ""
DotobjModelLoad(): "###"
DotobjModelLoad(): "Object voronoi.obj"
DotobjModelLoad(): ""
DotobjModelLoad(): "Vertices: 763"
DotobjModelLoad(): "Faces: 88"
DotobjModelLoad(): ""
DotobjModelLoad(): "###"

I wasn't aware of this at the time, but treating all lines that start with # will cause problems as some 3D packages use # prefixed lines to add additional data, e.g. #MRGB to define vertex colours.

(Also you should be checking for # prefix in the default case rather than for every single line.)