There's a known (by me) bug in LDView that is probably responsible for the error you see. I think if you remove the "_in_part" from the line, it will work. If not, if you send me your POV file, I'll see what fix can make it work.
Assuming this is the known bug, it is something that I have fixed in my development code, but not yet released.
Assuming this is the known bug, it is something that I have fixed in my development code, but not yet released.