Pretty much as you'd expect, it goes like this:
# xschmod
# Script to chmod the phpBBXS files
# Script must be executed from within the root directory
# of phpBBXS
#
chmod 777 ./album_mod/upload
chmod 777 ./album_mod/upload/cache
chmod 777 ./album_mod/upload/med_cache
chmod 777 ./album_mod/upload/wm_cache
chmod 777 ./cache
chmod 777 ./ctracker/logfiles/logfile_attempt_counter.txt
chmod 777 ./ctracker/logfiles/logfile_blocklist.txt
chmod 777 ./ctracker/logfiles/logfile_malformed_logins.txt
chmod 777 ./ctracker/logfiles/logfile_spammer.txt
chmod 777 ./ctracker/logfiles/logfile_worms.txt
chmod 777 ./files
chmod 777 ./files/thumbs
chmod 777 ./images/avatars
chmod 777 ./pafiledb/uploads
chmod 777 ./pafiledb/cache
chmod 777 ./pafiledb/cache/templates
chmod 777 ./pafiledb/cache/templates/ca_aphrodite
chmod 666 ./includes/def_themes.php
chmod 666 ./includes/def_tree.php
chmod 666 ./includes/def_words.php
# Script to chmod the phpBBXS files
# Script must be executed from within the root directory
# of phpBBXS
#
chmod 777 ./album_mod/upload
chmod 777 ./album_mod/upload/cache
chmod 777 ./album_mod/upload/med_cache
chmod 777 ./album_mod/upload/wm_cache
chmod 777 ./cache
chmod 777 ./ctracker/logfiles/logfile_attempt_counter.txt
chmod 777 ./ctracker/logfiles/logfile_blocklist.txt
chmod 777 ./ctracker/logfiles/logfile_malformed_logins.txt
chmod 777 ./ctracker/logfiles/logfile_spammer.txt
chmod 777 ./ctracker/logfiles/logfile_worms.txt
chmod 777 ./files
chmod 777 ./files/thumbs
chmod 777 ./images/avatars
chmod 777 ./pafiledb/uploads
chmod 777 ./pafiledb/cache
chmod 777 ./pafiledb/cache/templates
chmod 777 ./pafiledb/cache/templates/ca_aphrodite
chmod 666 ./includes/def_themes.php
chmod 666 ./includes/def_tree.php
chmod 666 ./includes/def_words.php
Using your favorite editor, put this in a file. mine is labelled xschmod. Place it in your newly extracted phpBBXS directory, make sure you give it execute permissions... e.g. chmod 755 xschmod. Then run it with ./xschmod. Voila, everything will have the right premissions in an instant.
Thought... why not modify the install scripts to create these files/directories with the right permissions?