You should report this to ReaKontrol's developer here:
https://forum.cockos.com/showthread.php?t=222331.
You can uninstall ReaKontrol from ReaPack > Browse packages if you don't use it. Since you mentioned getting the crash since after synchronizing ReaPack, you probably have the "Install new packages when synchronizing" option turned on. You can turn it off just for extension plugins like this in ReaPack > Manage repositories: