Upgrading Drupal

Is there an easy way to upgrade...I am quite worried that I'll get it wrong and screw up the installation :(

I've written a small, partial screen-scraping perl API to the Drupal admin pages. Its primary motivation is to allow me to script upgrades across multiple sites. There is a sample upgrade script included in the distribution (examples/drupal-upgrade). It attempts to follow the recommended upgrade procedure, including saving the module state, disabling non-required modules, and restoring the state after the upgrade. I must stress that this is ALPHA quality code, but I'd love to get some feedback if anyone is brave enough to try it.

I'm trying to update from 6.2 to 6.9 and I have the error message others have also reported, "array_pop() [function.array-pop]: The argument should be an array ... /drupal/update.php on line 315".

While I've followed the update instructions as best I can, I'm left with the update telling me there are no updates available.

I've have chased through many other comments, from trying running update in IE instead of Firefox and changing mod_security, but to no avail. If the answer lies with changing Apache permissions, I haven't a clue how to set about it.

I've upgraded from Drupal 5 to 6. The site is working smoothly with Garland themes. But, if I switch to my custom themes, it only displays blank screens everywhere (no errors, no html).
I'm not sure it's because of my themes registry.
I created new file (page-login.tpl.php). So, I added the following code in template.php.

function mythemename_theme($existing, $type, $theme, $path){
return array(
'user_login' => array(
'template' => 'page-login',
'arguments' => array('form' => NULL),
),
);
}

Hi there,
Some of you may know that OVH helps newbies like me to install Drupal with one click depending on the hosting plan you have.
Anyway they do not help as far as upgrading from 6.6 to 6.9

The instructions for upgrading clearly state: "Disable all custom and contributed modules."

I did that when upgrading from 6.8 to 6.9 and it was a pain. I had to do it four times to get through all the dependencies. By the end I felt a bit foolish. But this was my first Drupal upgrade, I played by the rules.

Then I asked one more experienced Drupal admin and he said he often skipped that step, he knew the modules would do fine.

So I want to ask you: Do you disable modules or not?