I had to uninstall minion because it blocked my internet access.
System:
Asus Maximus V Formula
Intel 3570K
EVGA GTX670 FTW SLI
OCZ Vertex 4 SATA III 2.5" SSD 128GB
WD Caviar Green 1T SATA WD10EZRX + WD Velociraptor 150GB + WD Caviar Black 640 GB
GSkill RipjawsX DDR3 1600 PC3-12800 16GB(4GBx4) CL9
Asus Xonar Essence STX'
Corsair HX1050W V2 80Plus Gold
Logitech G710+
BenQ RL2450HT
Razer Taipan
Windows 8.1 Pro (x64)
Very strange. What happens if you re-download it from http://minion.mmoui.com and re-install it?
If its the same thing you might have a bad installation of java on your system. Try un-installing java and then run Minion (Minion will use its own version of java if you remove your install).