how to change a name of primary links block???

Hello lmteijon,

well the answer is quite simple. Please follow these steps.
Attention: This is how it works for Drupal 5.0!

Changing the menu title

1. Log in as admin
2. klick the Administer link
3. klick the Site building link
4. klick the Menus link
5. navigate to Primary links and klick the edit link
6. now change and save your menu title

Changing the block title

1. follow steps 1 to 3 from above
2. klick the Blocks link
3. navigate to Primary links and choose configure
4. here you can overwrite or delete the block title

Have a look at the documentation too. Here are the links for Blocks and Menus.

Blocks: http://drupal.org/handbook/blocks
Menus: http://drupal.org/node/37375

I hope I could answer your question?

With best regards

Mike