I have acttually created a /tmp directory in my mediawiki directory and made it writable, I've also gone into the PHPTAL.php and changed the TMP variable to a foll path ie. /home/virtual/site22/fst/var/www/html/wiki/tmp, but that still results in the install seeming to hang at "Warning: $wgProxyKey is insecure"
What dit you change exactly in PHPTAL.php?