GUI Not displaying

Since the last update I have been unable to load the GUI to make changes.  The loot and other modifications are working and the plugin loads without error message.  However, on each of the servers I am unable to get the GUI to load.

Image Library - latest
Oxide version: 2.0.6198 
Server version 14255935
Loottable version 1.0.36

I am happy to provide you with any other info you need and perform any troubleshooting steps required, though it may take me a while to respond each time due to RL obligations.

Plugin is hosted on a bare metal server and I have root access.

Make sure you have the required permissions

Edit and debug perms both assigned.  

This is in the oxide logs after using the /loottable command.

[Error] Failed to call hook 'CMD_loottable' on plugin 'Loottable v1.0.37' (DllNotFoundException: libgdiplus.so.0 assembly:<unknown assembly> type:<unknown type> member:(null))
  at (wrapper managed-to-native) System.Drawing.GDIPlus.GdiplusStartup(ulong&,System.Drawing.GdiplusStartupInput&,System.Drawing.GdiplusStartupOutput&)
  at System.Drawing.GDIPlus..cctor () [0x000b0] in <04abc238e1e64b378e01047493bf1e72>:0

Edited May 13 by Rome74