Cant log into Nexus mod manager

[CerealBoy]

For the past three days I've been trying to log into the Nexus mod manager, but every time I do I get an error message saying

 

"Could not load file or assembly 'SMDiagnostics, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The module was expected to contain an assembly manifest."

 

I've tried re-downloading the program, made sure that my firewall wasn't blocking it from working, tried using an older version of the program, and restarting my computer. I've used Nexus mod manger before, but that was about a year ago, and I had no issues then.