When i go online, i try to go into a game, but then it tries to connect to the host, and this comes up:

Error: cannot get checksum15

I just downloaded the latest patch, extracted the files in my documents, but where in the worms Armageddon folder do i move them?

Thanks BTW! :)

you should extract the patch in the Worms Armageddon directory itself to make it work correctly or you can use CyberShadows installer.
http://worms.thecybershadow.net/files/WA_update-3.6.26.5_Beta_Installer.exe

Done, should it work now?

It said it had to replace a lot of files, is that normal?

sure
patch and update made to replace files that need to be replaced... nothing to think about - just replace =)