Bug FXML LoadException

Code (Text):

1. javafx.fxml.LoadException:
2. /C:/Users/Torben/RuneMate/temp/-355813590.res
3.  
4.     at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601)
5.     at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2579)
6.     at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
7.     at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2409)
8.     at nul.iIIIiiiIIiii.new(zn:186)
9.     at nul.iIIIiiiIIiii.new(zn:122)
10.     at nul.IIIiIIiIiIIi.<init>(rsb:11)
11.     at nul.IIiiiIiIiIII.new(fzb:20)
12.     at nul.IIiIiIiIIIII.new(umb:193)
13.     at nul.iIIiIIiIiIii.new(opb:4330)
14.     at nul.iIIiIIiIiIii.call(opb:2513)
15.     at javafx.concurrent.Task$TaskCallable.call(Task.java:1423)
16.     at java.util.concurrent.FutureTask.run(FutureTask.java:266)
17.     at java.lang.Thread.run(Thread.java:745)
18. Caused by: java.lang.NullPointerException
19.     at nul.IIIiIIiIiIIi.initialize(rsb:189)
20.     at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
21.     ... 12 more
22.  

Happens sometimes while navigating through pages
@Arbiter