[Solved]: Cannot change config settings, database seems readonly

[lalalala]

This is my first post here, trying to be as specific as possible but I am a newbie.
I am trying to set up coppermine1416 on a small ubuntu server. Installs without complaints. Looks good in browser.
Now, I cannot change any settings in admin->config. No errors are generated, just nothing changes.
Can't find any errors  in logs either. Seems like the database is readonly for user la from coppermine but the user la has full access and can change values in phpmyadmin. If I change things with phpmyadmin, changes are visible in coppermine admin.

Have checked in docs and FAQ for similar problems.

I have another server with coppermine that works, I have not so far found any differences in setup btw. good and bad server.

(I have set debug_mode to 1 manually in phpMyAdmin)

Attached are Debug results of trying to change "Timezone difference relative to GMT" from 0 to -1

What can I do more now?

[Nibbler]

File is empty. If you lacked perms on the database tables you would get an error message.

[lalalala]

Please say what file you are referring to. I am probably missing something basic??

In mysql there is a database named cpg1416 (created by me for coppermine, populated by coppermine install) that has a table cpg14x_config that has name value pairs like gallery_description etc. These are not changeable from coppermine::admin, but they are readable.

[lalalala]

Oops,
failed to check the included file. Here is a new try to include the Debug results.

[Nibbler]

Why is your post_max_size set to 1024 bytes? That's probably too small to even allow posting the config form.

[lalalala]

I don't know. I have not intentionally changed it. 

Where to change it and to what?

[Nibbler]

php.ini - default is 8M

[lalalala]

Changed to 8M as you suggested.
restarted apache,  changing settings in coppermine::config works now!!

Checked in my other working coppermine server, there it was already 8M

Thank you for your great help.
Thank you for your speedy answers too!