I too am having this issue. I cannot download anything. It started late last night at around 3am Arizona time. It worked momentarily and I was able to download a mod, then the error box began popping back up again.
I must say, I am very pleased to have found this! I'm downloading the mod as I type. I have a huge crush on Nick *giggles* and I'd like to thank all involved for making this mod. Good work everyone and thank you!!