SF Treadmill - Error Message

When i use the treadmill, i receive the following error:

[16:46] SF Treadmill: llTextBox: First parameter must be a valid agent key

After that, a text box pops up gyazo.com/345337a00ee1beb3cc08111de8603092



It is still usable, still gives kWh, etc. 
Not sure what the error means or how to fix it.