Has anything changed - a software version upgrade or uninstalled something else since you last used it?
JIT Debugger errors are usually caused by corrupt and/or missing .net framework packages.
What OS are you using and which versions, if any of the .net framework do you have running?
more info/download links for all the different .Net packages are here
Even if you get a JIT debugger enabled, it may not make a whole lot of sense unless you're code savvy, so luckily zboards US distributor steelseries have a support address