Debug paste link:
https://hastebin.com/gaculuniho.java

Description and relevant errors:

Make sure you've done the following:

• You're using the latest build for your server version
• This isn't an issue caused by another plugin
• You've checked for duplicate issues #478 is the same exception but not the same error
• You didn't use /reload

Issue is with the GPS plugin, contact the author of it.