I just downloaded this plugin on a small test server. The server had no issues at all before installation, and has very few plugins installed to begin with.

During the server startup, the following errors appear:
http://pastebin.com/WMmyP4pL

I am currently using a different spawner plugin on the main server, but it seems to be throwing entity errors. Since I saw SilkSpawners was updated so recently for 1.9.4, I thought there wouldn't be any errors like that. However, I still encountered these issues.

Can you please pastebin your localization.yml, too?

Regarding the log message, I need to debug MC server a bit more, since it seems like a Vanilla log message.

localization.yml:
http://pastebin.com/X1sTTXaj

Your localization.yml is invalid - have you modified it? Does the issue persist, if you delete it and restart your server?

I had the plugin regenerate a new one, and I didn't touch it this time. No more error. I'm not sure what went wrong; I only changed a few words here and there for my own grammar preferences. Oh well. I'll just leave the default to avoid that happening again. Thanks for your help.