Upgrading Drupal

Hello,
I am resurrecting an old website and am wondering the best path to upgrade to the present. Also, should I upgrade to 6.4 or 5.10?
My existing site is fairly straightforward, mostly consisting of a weblog with categories etc.

thank you for any help
Polgard

This warnings appear both on localtest and live, and of course after disabling all contrib modules as suggested:

* warning: array_merge() [function.array-merge]: Argument #2 is not an array in /.../public_html/update.php on line 174.
* warning: Invalid argument supplied for foreach() in /.../public_html/update.php on line 339.

Any hint? Though it doesn't seem to be serious. Thanks

Hi Y'all

BACKGROUND
I recently upgraded my solo-blog all the way from Drupal 5.1 to 6.4. The only issue I had was I seemed to have lost my free-tagging taxonomy terms (I used taxonomy-dhtml in 5.1 to list categories on the right-pane eg: "Linux(3)" for 3 hits in the Linux category).

I've set up a test site to try upgrading from version 5.10 to 6.4. Overall things look good, except on a few pages where I need to use some PHP code to pull data out of a legacy database. I get these errors:

Parse error: syntax error, unexpected '>' in /home/site_name/public_html/drupal6/includes/common.inc(1547) : eval()'d code on line 1

Which I understand means I supposedly have errors in my PHP code. It worked fine in 5.10, so I'm not sure what the problem is here. As a test, I tried replacing the code with this:

Hi

I must confess, that I was maybe a bit brave this time, upgrading directly from version 5.6 to 6.4.

The site seems normal, but now users get to add book pages, even though the book module isn't (and wasn't) active, and they haven't got permissions to add, edit or delete book pages. They also get to add pages, without the necessary permissions.

Hello,

I've just completed my update to Drupal 6.4. However, I'm stuck at this step:

"12. Re-enable custom and contributed modules and re-run update.php
to update custom and contributed database tables."

My URL's have changed since I de-activated pathauto to run the install.

Please tell me the URL needed to re-activate my modules.

Thanks,

Daniel