Failed to run a 1.00 timer in 'BuildingSkins v2.0.10' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.BuildingSkins.OnPlayerConnected (BasePlayer player) [0x00073] in <51c076058e2d44b5be8248c02162f93e>:0 
  at Oxide.Plugins.BuildingSkins+<>c__DisplayClass14_0.<OnPlayerConnected>b__0 () [0x00000] in <51c076058e2d44b5be8248c02162f93e>:0 
  at Oxide.Core.Libraries.Timer+TimerInstance.FireCallback () [0x00018] in <beb2b64691c64e2b95b99491bd85442c>:0 

Installing the image library dependency fixes the error. Install dependencies when a plugin requires them.

imagelibrary is installed and loaded before this plugin load so it don't fix the issue...

I have image library installed and I too have the error. Image Library loads fine. No issues.

It's strange. It's what fixed the error for me. But now I can't replicate the error by deleting Image Library with the outdated server nor with an updated one. The plugin just runs and compiles fine. @Bumfuzzler@Tanki