Upgrade (big) problem

[design]

Hi everybody.
I did an upgrade (in reality I did it twice, but with the same result) from 1.4.7 to 1.5.4.

After the upgrade the problem is:

-I don't see any file list in the frontend (but files are visible in backend)
-I don't see any template in the backend area (admin zone)
-In the frontend Images gallery: i see all the thumbs, but if I click on an image then I can't see the larger version (in fact, the system rewrites every single image url like this: content/images/temp_5588826b3d7ad2e57da4513acd366eac.jpg - so adding a temp_)
-charset problem.

So after five hour of tries I'm asking you: have you got any idea?

PHP version: 5.3.10
MySQL: 5.1.x/community edition
Apache: 2.2.x
Os: Centos 5.8 64bit

[juergen]

This looks like a need of checking charset settings mostly in the Database section. Did you change anything? Did you checkup new against old conf.inc.php ?

[Oliver Georgi]

…it can be anything, don't think it is a charset related problem. More a path problem and/or missed upgrade steps.

[design]

Because I needed two sites living together (the old version with old graphic design) and the new one (new cms version + new graphic) I duplicated the DB. And probably something went wrong. So all the problem was in my new DB. In fact, I did a simple and easy test: I just change the DB connection in my new config file directing to my old DB.
Everything is fine. So the problem was in the new DB, as you supposed.
And I feel so stupid!
Thank you so much for your attention.