Hey, I am sorry you are having problems. Some other users have had this exact error as well. It means that one networking library I use cannot start. For one user, this was because their anti-virus was stopping the client from making a 'loopback' interface–basically a localhost-only port so the program can talk to itself. It could also mean that a dll has failed to load, likely again due to anti-virus calling a false-positive and blocking it. Another user had a unicode character in their PATH environment variable, which python 2 couldn't deal with.
This is not my code, so I cannot do a huge amount to fix these problems on my end. I actually tried to swallow this error in v279, but I guess it happens before I get control from the bootloader.
In any case, please try running this debug release:
https://www.mediafire.com/file/nc58o18kbqx3et5/Hydrus%20Network%20279%20debug%20-%20Windows%20-%20Extract%20only.zip
Just extract it somewhere fresh, then go shift-right-click->open in command window on the folder and then type either 'client' or '.\client' (if you are in the powershell). It will attempt to load with a lot of debug load information, and hopefully a nice error. Take a screenshot of the error and post it here or email it to me!
BTW: you shouldn't have to have python installed to run hydrus. If you are running the built executable I put out, everything you need (including an embedded python runtime) should be included.