If you need further details let me know, fails to load mod because of this error.
Also, in 0.15.4 the underground 30s/50s not working, they are the standard length.

Cheers!
Satscape

0.15.5 has Missing Textures,- Confirmed.:)
Salute.

That´s because the textures are a little borked. As a temporary fix go in:

5dim_transport_0.15.3.zip\5dim_transport_0.15.3\graphics\icon\pipe\

and rename "icon_5d_pipe-to-underground_30_.png" to
"icon_5d_pipe-to-underground_1_30_.png

and "icon_5d_pipe-to-underground_50_.png" to
"icon_5d_pipe-to-underground_1_50_.png