Hi,
I had a problem when updating the module languages and wanted to share its solution.
A 403 error was launched when updating the module languages. I don't really know why it was produced, but it was fixed activating post_max_size in the general php.ini and setting a php.ini in the specific directory increasing upload_max_filesize and post_max_size of the directory (as my server admin told me).
First approach was to check the permissions, but they where right. I test everything I though of, but nothing seemed to work. Finally, I test to remove some modules and leave less module languages. When there were enough few modules, it worked.
I continued that way and check the server properties. Everything seemed to be ok, but it was quite odd that the process ran ok with few modules and produced a 403 error, which is a permissions error, when there was all of them.
I thought that the problem might be in the POST sending. And so it was. A form with less than 1000 fields was sent ok. A form with 1000-2000 fields was sent, but only the first 1000 fields were received. A form with more than 2000 fields was not sent, and a 403 error produced.
I test it with a simple script, which creates a form with a given number of fields. I attach it to this post, just in case it is useful for anyone.
So, the number of fields in the form was the key of the problem. Not so the size of the form POST sending, as it was 5-15 KB (for the test script, 167 KB for the module languages). Therefore, I don't understand why the upload_max_filesize must be increased to 64 MB, if the sending was just 5-15 KB.
postFormTest.zip