Windows 8 Problem Downloading because of Signature Validation

Hi! I'm having problems downloading a program called HOT2000 onto my laptop. Every time I go to download it this thing pops up and it sucks. I have tried restarting like it suggests and selecting and deselecting the checkmark and restarting again. I'm not sure if this is a hard problem to fix or not but please let me know! if any more information is needed just say so! Thank you!