error

I get this error when I try to edit a node under Drupal 6x: "This content has been modified by another user, changes cannot be saved.". It happens just sometimes and it does not matter how many times I re-send changed text. But it works when I click on "edit" tab and make changes again. Nobody else has access, also there is not an editor-conflict. any idea why?

Any idea why nothing changed after updating weight in navigation-menu? It works when I try it individually using menu-point... >> edit and change weight-number. But when I change weight under "admin/build/menu-customize/navigation" , a message like "* Changes made in this table will not be saved until the form is submitted." appears above submit button. Than I click on "save configuration" button but nothing changed. Any idea? It is Drupal 6.10. Menu elements are like below:

Blogs	

My blog	

Books (disabled)	

Catalog (disabled)	

Compose tips (disabled)

If you get this error:

• install Drupal SMTP Module: http://drupal.org/project/smtp
• download & extract phpmailer to modules/smtp/phpmailer : http://phpmailer.sourceforge.net/
• dont forget to rename "modules/smtp/phpMailer_vx.." to "modules/smtp/phpmailer"
• Turn SMTP on : admin/settings/smtp
• double check your auth-settings

After I have installed some modules and activated them, admin-menus-navigation-edit gives page not found error. Any idea?

Importing interface translations

Error importing interface translations
Please continue to the error page
An HTTP error 404 occurred. /batch?id=10&op=do

This happens when I try to add a language. There is no problem if I try it with Internet Explorer. I am using Drupal 6.9 and Firefox 3.0.6.

Any idea?