The selected file sites/default/files/tmp/xxx could not be copied.

I have spend a week to resolve this problem but suggested solutions here and reports of bugs in earlier versions didn't apply to my problem. (This means that i ve found posts related to this error submitted the year 2007)
Please i need help from advanced users to make the last attempt before applying my latest backup
I wiil explain what changes i ve done that might be responsible for this
1. Upgrade to the latest version of drupal 6.13 from 6.11
then upgraded all installed modules : views, fck editor , imce, image,web links 10n client, to the current stable or dev versions
in order to install bg gallery i got also installed in the same time jquery update.
And that was the initial for getting the errors that are visible in the home page and in every post for visitors and also in the admin page . Tried to cmod the entire files folder and subfolders. Also create a new directory of files in the root and apply this to the module in vain
So what i have done firstly was to remove bg gallery update php clear cache and remove also a bg table from data base with php my admin. then removed jquey_update module and place the standard drupla files in folder misc
then i removed all modules that handle images disabled upload_ module ,10n client cleared cashe 50 times , update php
I dont know any more what to do
the url of the site is http://1dim-giann|dot|pel|dot|sch|dot|gr
information about status report
FCKeditor Unknown
File system Writable (public download method)
GD library 2.0 or higher
MySQL database 5.0.45
PHP 5.2.5
PHP memory limit 48M
PHP register globals Disabled
Unicode library PHP Mbstring Extension
Update notifications Enabled
Web server Apache/2.2.6 (Unix) PHP/5.2.5
Zlib library Enabled

in the log i get repeted every time i view a page this error
locale
Ημερομηνία Παρασκευή, 31. July 2009 - 7:21
User Ζωή
Location http://1dim...gr/?q=el/admin/reports/status
Referrer http://1dim...gr/?q=el/admin/reports/status
Message An error occurred during creation of the JavaScript translation file for the language Greek.
Severity error

I am really confused how I solved this problem.

Non of the solutions I found on forums helped me to solve the message "The selected file sites/default/files/tmp/xxx could not be copied".

All solution I tried and did NOT work:
- check I was running PHP safe_mode OFF ( PHP was not in save_mode so that is correct)
- create the folder DRUPAL-ROOT/languages and chmod 777
- creater the folder DRUPAL-ROOT/sites/default/files/languages and chmod 777

After spending hours and hours I decided to change the owner of the DRUPAL-ROOT/sites/default/files/language folder to www-data (it was root 777). I still don't understand but chow www-data.www-data on DRUPAL-ROOT/sites/default/files/language solved the problem for me.

Why does 777 owner and group root fail and 777 owner and group-data works correct?

I didnt have a languages directory - /sites/default/files/languages
I got onto this from other posts. Creating this directory from filezilla with default permissions.

This solved the problem for me. Running Drupal 6.13 (old installation laying stagnant for nearly a year).

As i have tried all the responses here, none of them seem to resolve my problem.

i got the error in dutch:

Het geselecteerde bestand C:\WINDOWS\Temp\fil7A80.tmp kon niet geladen worden omdat de doelmap languages/nl_c2c922aa75cbfb116ee333c4523fbf72.js niet gevonden werd of omdat de toegangsrechten niet toestaan dat het bestand daar geschreven wordt.

in english:

The selected file C:\WINDOWS\Temp\fil7A80.tmp could not be uploaded, because the destination languages/nl_c2c922aa75cbfb116ee333c4523fbf72.js could not be found, or because its permissions do not allow the file to be written.

However i did found the solution on Drupal.be forum

It turns out that my temporary directory was set incorrect. I had to change it on /admin/settings/file-system

Hope this helps someone