yeah I can join others and I was able to join his before, but now this is happening.
It's something with this Blockland files if you can join. Blockland loads everything server sided, meaning it uses all of the files from the Blockland folder on the person who is hosting. That is why sometimes when you join certain servers the brick textures are different.
Tell your friend to re-install Blockland, before that though since you have a fresh install of BL find a way to send the init.cs.do file to your friend and then see if you can join. If not then tell him to reinstall Blocklsnd. If that fails then he probably port forwarded wrong or somethig which I doubt if you said you were able to join before.