You could check in the php error log on the server what the error is, but if you get a white page it might just be that you don't have a good copy of your database. I'm not sure how you imported your database but phpmyadmin is not so good at that. You could use bigdump or an alternative approach using backup_migrate module. 
  1. Install backup_migrate on the live site, take a backup with it
  2. Copy all files to the test site
  3. Replace on test settings.php with a new fresh copy from default.settings.php and do a new fresh install of Drupal
  4. Enable on the fresh install the backup migrate module and restore the backup
As for the cache, you can truncate all tables starting with cache_ in the database or use the function http://api.drupal.org/api/function/cache_clear_all/6

Hans
www.koba.be


2010/1/4 Daniel Carrera <daniel.carrera@theingots.org>
Domenic Santangelo wrote:
> On Jan 3, 2010, at 2:48 PM, Daniel Carrera wrote:
>
>> There was no $base_url set, but setting it did not fix the links. I
>> tried clearing the cache but that didn't help, but then again, maybe it
>> was giving me the cached page from the usual site. How do I clear the
>> cache manually? Is it save to just write "DELETE * FROM <...>" for every
>> cache_* table?

<daniel kicks his computer>

I'm really tempted to throw my computer out the window.

Daniel.
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