for the first host, i would double check that session management is functioning, try the session test file from the following thread:
showpost.php?p=23826&postcount=2
if the session test fails, you will need to contact the host to have session management fixed, most likely is it a problem with the session.save_path in the php.ini file.
for the second host, it sounds like the installation was already run, maybe on a different server.
delete the Connections folder and start the installation again.