Upgrading Drupal

Hello, in end of june 2005 I decided to create a new site. Since Drupal was out for a long time I decided to use CVS (actually it was called HEAD) and I noticed differences with my other drupal site, but all is working fine, except when I then tried to update to 4.6.3 then I had only mistakes relating to function names having changed and god knows what else, so I reverted it back to the files I installed in the first place..

Now, how will I be able to update to drupal 4.7 ? Because I really want to.
What would be the process ?

I upgraded to 4.6 and had some issues with errors on taxonomy terms so I decided to start fresh and create a new database , importing the node , user, user permissions tables, however when I try to create new content.

I get old content popping up, each time I create content, this value increments by one, currently at node/60 however I have over 1500 pages, How can I make it jump, to 1500, or do I manually have to edit items into database from now on.

perhaps there is a table I can import that can tell drupal to start a totally new page.

I have a problem with my current version of drupal the search engine friendly urls work for the most part, but occassionally they turn into the big long urls. Some of them have been indexed. I'm a little afraid this will lead to a penalty from search engines for duplicate content.

Is upgrading the solution? If so I have another issue. Every time I try to upgrade the menu on the left completely disappears. Here's my address if this helps http://tvcrazy.net/forum/

Story here: http://www.cesspit.net/drupal/node/899

The site may go down since I'm messing with it and trying to update.

In short, I had corruption problems that messed completely my database. This happens if you dump the db with the *default* options.

By default the new mysql versions (4.1.x) consider the database as latin1. But the mysqldump and phpmyadmin wrongly default as utf8. Resulting in corrupted data.

I had this error in version of 4.5 and when I updated to 4.6, I get the same error.
I've been searching for a solution, But I have had no luck so far.

This are the type of errors I get
http://www.footballclips.net/images/error_drupal.jpg

After hours of frustration, and numerous attempts, (mostly involving changing file permissions and retrying), I have finally arrived at this error message. And am stumped with knowing how to proceed.

Fatal error: Class 'BaseTheme' not found in /var/www/html/drupal462/themes/xtemplate/xtemplate.theme on line 15

Any help?