The plug, with no modifications, loads fine for me as well. The debuglog.txt outputs the following:
loading object data
warning: Yethelip (777) lacks landing description
warning: Yethelip (777) has a bar but no bar description
warning: Xylep Sensor Beam (444) lacks outfit picture
warning: Xylep Sensor Package (445) lacks outfit picture
warning: Xylep Jammer (446) lacks outfit picture
warning: Xylep Cloaking Device (447) lacks outfit picture
warning: Xylep Cloaking Device (447) lacks description
warning: Xylep Plasma Torpedo Launcher (448) lacks outfit picture
warning: Xylep Plasma Torpedo Launcher (448) lacks description
warning: Xylep Plasma Beam (449) lacks outfit picture
warning: Xylep Plasma Beam (449) lacks description
warning: Xylep Disabling Beam Mark II (456) lacks outfit picture
warning: Xylep Disabling Beam Mark II (456) lacks description
warning: Xylep Interceptor (406) lacks purchase description
loading mission data
propagating mission bit effects
showing splash screen
loading sprites
checking memory
loading ship sprites
warning: Xylep Interceptor (406) lacks target picture
warning: Xylep Interceptor (406) lacks shipyard picture
configuring sprites
The bold sections are the warnings. These are non-critical items that, while they shouldn't be causing Nova to crash, should probably be fixed if you plan to release your plug.
As always, when testing a new plug, make sure that you don't use any other plug-ins, as well as any pilots that have outfits/ships/etc. that are modified by your plug-in. This will help to prevent errors.