Reinstalling did it, thanks man. I moved the folder as I didn't want space in my SSD to be used up, maybe you guys can allow for custom installation paths in the future.
I'm having a similar issue, log as follows:
[Debug] RuneMate Version: 2.1.6
[Debug] Java Version: 8u92 x86 (Oracle Corporation)
[Debug] Operating System: Windows 10 x64
java.lang.InternalError: instrument library is missing in target VM
at...