I have another idea
Step 1 - Close ANY program that uses java
Step 2 - Check your processes list and make sure there is no java.exe processes running
Step 3 - If there is any java.exe processes running. End task them and try opening RR again.
Sometimes when I ran RealmRelay, it wouldn't close properly and stopped me from running it again after that until i closed the java.exe process that was running in the first place.
Let me know how you go.
EDIT: I just emulated your situation by opening a 2nd RealmRelay