I ran into the same issue. I'm using a do file that's worked well in the past and all of the sudden am getting this same error after setaccess. I ran the commands listed and get:
. net install twitter2stata, replace
checking twitter2stata consistency and verifying not already installed...
all files already exist and are up to date.
. which twitter2stata.ado
/Users/abbykinch/Library/Application Support/Stata/ado/plus/t/twitter2stata.ado
*! version 1.0.4 13dec2017
. which twitter2stata-1.0.4.jar
/Users/abbykinch/Library/Application Support/Stata/ado/plus/jar/twitter2stata-1.0.4.jar
So I'm not sure what's wrong. Any help would be awesome.