Why am I receiving an internal error with Burnup Chart?

[IT]

Received an internal error with the Project Burnup Chart plugin by cPrime Labs. Unable to change any of the fields to make the error go away. We are using JIRA 6.2.7. BurnupError.PNG

Doesn't matter what project we use, and even if the versions haven't expired, get the same error. Tried different issue types too. 

Please offer some assistance.

Thanks!

[IT]

Their other plugin works for our version of JIRA. The Actuals vs Estimates Chart is half of this plugin and that works for us. The graph itself is having problems pulling data. I have a feeling it's not compatible with our version. 

[Chag]

have you tried looking at the logs when this happens?