Both in singleplayer and on someone elses server, if I try to place a blueprint which doesn't even uses pipes or anything this mod does it crashes the game/server with this notice:

The mod Pipelayer (0.4.4) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event pipelayer::on_put_item (ID 9)
Item is not blueprint.
stack traceback:
pipelayer/lualib/BaseEditor/BaseEditor.lua:674: in function 'on_player_placing_blueprint'
pipelayer/lualib/BaseEditor/BaseEditor.lua:1137: in function 'on_put_item'
pipelayer/control.lua:46: in function <pipelayer/control.lua:46>
stack traceback:
[C]: in function 'get_blueprint_entities'
pipelayer/lualib/BaseEditor/BaseEditor.lua:674: in function 'on_player_placing_blueprint'
pipelayer/lualib/BaseEditor/BaseEditor.lua:1137: in function 'on_put_item'
pipelayer/control.lua:46: in function <pipelayer/control.lua:46>

Are you trying to place a blueprint from the blueprint library, either directly or as a toolbar shortcut pointing to a blueprint (or book) in the library?