I have an Omeka 2.2.2 install with the following plugins: Coins, Exhibit, Neatline, Neatline Text and Simple Pages. I have now uploaded the Dropbox plugin and set the permission to files to 755 but I am getting this error when I click on the plugin tab from the dashboard:

parse_ini_file(/srv/data/web/vhosts/bohdanpawlowicz.org/htdocs/suitcase/plugins/Dropbox/plugin.ini): failed to open stream: Permission denied

There is a whole series of lines (from 1 to 14) mentioned in the blank area.
I have already deleted the whole folder from the server and uploaded it again but the pb continues. What am I to do?

You deleted the Dropbox folder and that error message is still shown?

No. When there is no Dropbox folder the plugin dashboard works normally.

It just sounds like, when you're installing Dropbox, you're not giving read access for the plugin.ini file, so Omeka can't read it.

Check the permissions on both the Dropbox folder and the plugin.ini within (and other files). Usually, the normal default permissions are fine and its only the "files" folder inside the Dropbox that needs to be changed at all.

I have given permission to the files folder (755, right?). However, there are two files outside the files folder: the plugin.ini and the Dropbox php file, which do not sport any permission. What permission should I attribute to them?

OK..the other plugin inis (Coins, etc...have a 644 permission) so I suppose I should use the same.

No..not right. I changed the permission to 644 and when I try to get the plugin from the dashboard I get the following error message now:
Warning: require_once(/srv/data/web/vhosts/bohdanpawlowicz.org/htdocs/suitcase/plugins/Dropbox/helpers/DropboxFunctions.php): failed to open stream: Permission denied in /srv/data/web/vhosts/bohdanpawlowicz.org/htdocs/suitcase/plugins/Dropbox/DropboxPlugin.php on line 18

Fatal error: require_once(): Failed opening required '/srv/data/web/vhosts/bohdanpawlowicz.org/htdocs/suitcase/plugins/Dropbox/helpers/DropboxFunctions.php' (include_path='/srv/data/web/vhosts/bohdanpawlowicz.org/htdocs/suitcase/application/libraries:/srv/data/web/vhosts/bohdanpawlowicz.org/htdocs/suitcase/application/models:.:/usr/share/php:/srv/data/web/includes:/srv/data/web/vhosts/bohdanpawlowicz.org/htdocs/suitcase/plugins/ExhibitBuilder/models:/srv/data/web/vhosts/bohdanpawlowicz.org/htdocs/suitcase/plugins/ExhibitBuilder/libraries:/srv/data/web/vhosts/bohdanpawlowicz.org/htdocs/suitcase/plugins/SimplePages/models:/srv/data/web/vhosts/bohdanpawlowicz.org/htdocs/suitcase/plugins/Neatline/models') in /srv/data/web/vhosts/bohdanpawlowicz.org/htdocs/suitcase/plugins/Dropbox/DropboxPlugin.php on line 18

OK..I finally managed to make it work by comparing the permission of each item in the Dropbox folder to the Exhibit folder and giving the files the same permission. I noticed that none of the files in the Dropbox folder (with the exception to the ones I had already changed) had a permission - they were all blank.

Basically, Omeka needs at least read permission to all the files in the plugin. It might be best to try applying some permissions to the whole plugin at once.

In the instructions on how to install the plugin it is said to change the permissions only for the "files"folder, which I did. I had no idea that the files inside the other folders had no permission at all and this is the first time this happens to me. Thanks for your help anyway.

As I said, usually the default permissions are fine. There being "no" permissions on any of the files is a very rare scenario.

The permissions that are set in the .zip of Dropbox on the addons directory are as they should be, so these permissions problems may have occurred on your end somehow, maybe when you were transferring or moving the files.

Hmmm...can they change like that on their own? I transferred them using Filezilla. Unzipped the downloaded zip on my computer and then just uploaded the whole folder without doing anything. Then changed the permission to the files folder on the server (without success) and only later noticed the discrepancy.