Take a look at PHP memory_limit req, a page that has been hit over 17 thousand times! TikiWiki wants 32megs as the memory_limit. Anything less is asking for trouble.
After you install you can learn all about these limits by running the program PHP Info, which is the bottom most menu item after logging in as Admin. (http://www.YourSite.com/tiki/tiki-phpinfo.php). Run that and search for three values on your ISP’s server:
max_execution_time = 300 ; Maximum execution time of each script, in seconds
max_input_time = 60 ; Maximum amount of time each script may spend parsing request data
memory_limit = 32M ; Maximum amount of memory a script may consume
From my personal experience an 8M memory limit can bomb sending out just 50 newsletters. I'm told the upper bound for this would be around 4000 on a very well kept server with the full 32M memory_limit.
Do not assume because your ISP has Fantastico or some other install script or advertises TikiWiki as supported that they have any experience whatsoever in this. Few offer more than the 8MB install default of PHP so be advised. The problem doesn’t surface till the loading starts. --RickL
TikiWiki 1.7.2 FTP installation guide
I've installed tikiwiki (1.7.2) just a few minutes ago for the first time and am writing this immediately after the installation.
If you are trying to install tikiwiki to your webhosting account and you have only FTP access (no telnet, SSH), read on:
steps:
1. Download the latest tikiwiki and extract the contents on your local computer.
2. Create a folder anywhere under your web root. For example: tiki
3. Upload all the extracted files to that folder.
4. CHMOD the following such that PHP can write to them:
- backups (if you plan to use backups)
- db
- dump (if you plan to use Wiki dumps or export the Wiki) and dump/html
- games (if you plan to enable game uploading) Make sure that games/thumbs and games/flash are also writeable.
- img/wiki (if you want to use drawings)
- img/wiki_up (if you want quick picture uploading to wiki pages)
- modules/cache (Mandatory)
- temp (if you want to enable batch uploading)
- templates_c (Needed to run tiki)
- templates
- styles
- lib/Galaxia/processes
(Note 1: in my case, I CHMODed 777 to all these, which makes them readable and writeable by anybody on the system, including the PHP and Apache programs. Some hosts dislike this, and require 755 permissions.)
(Note 2: most FTP utility programs will ask you whether you want to CHMOD the directory only or include the files under it. Choose with the files under it. For those who are not familiar with CHMOD, here are a short tutorial and a more complete tutorial. — Jean-François
Permissions work like this:
700 would give you -rwx-- in the directory listing
755 would give you -rwxr-xr-x in the directory listing
(r=4, w=2, x=1 with the digit positions representing owner, group,
others in that order)
This might look like:
chmod 777 -R backups db dump dump/html games games/thumbs
games/flash img/wiki img/wiki_up modules/cache temp templates_c templates
styles lib/Galaxia/processes
)
5. Have the mySQL db, userlogin, userpassword ready. Ensure that the user has full rights to the db.
6. Using a tool like phpmyadmin, navigate to the db, click on 'SQL', click on 'choose' button besides 'or Location of the text file', select the tiki.sql in 'db' folder on your local computer. Press 'Go' button
7. Now that you've populated the db w/ tikiwiki tables, open up tiki-db.php in notepad/wordpad and enter the db info. You can leave the $tikidomain = ''; as is. Save it
8. Replace the existing db/tiki-db.php in your webserver w/ the one you saved in above step.
9. Go to http://yoursite.com/tiki/tiki-index.php and
you should see some page displaying an error message since you won’t have permission to access any feature yet. Perhaps, you may need to follow instructions given on http://sourceforge.net/tracker/index.php?func=detail&aid=796457&group_id=64258&atid=506846.
9a. Sometimes, for whatever reason, you may need to try going directly to the admin page at http://yoursite.com/tiki/tiki-admin.php. Things will usually work fine from then on, but que cera.
10. Delete the tiki-install.php file. Jann Röder notices that local.php doesn't exist with this install procedure leaving the Tiki open to very bad things without this step. I wonder if creating a local.php instead of editing tiki-db.php at step 7 could eliminate this step. Chealer9 --- tiki-db.php already calls local.php, there's no need to edit it. Just create local.php with the proper variables daaave
11. Login as admin/admin and change the pwd.
Congrats! You've installed tikiwiki successfully. 
-
For people with FTP and SSH access to web serwer
Uploading an extracted Tiki takes very very long. There are thousands files in Tiki. So here is a faster way of achieving step 3 of the above instruction.
3a. upload tikiwiki-VERSION.tar.gz
3b. execute following commands:
tar -xvzf tikiwiki-VERSION.tar.gz
cd tikiwiki-VERSION
cp -R * ../
rm -Rf *
cd ..
rmdir tikiwiki-VERSION
rm tikiwiki-VERSION.tar.gz
...and you've saved a lot of time! 
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