http://blog.nemy.net/ returns a page to me. Seeing that page tells me that MAYBE the value for $baseurl in your conf/_basic_config.php file is incorrect. I am not very good at this sort of troubleshooting but saw what I saw and thought perhaps it might help you go forward.

I verifé the URL is the maid.
$baseurl = 'http://blog.nemy.net/blogs/';

You might be having memory limit errors (1.8.2 needs more memory than the previous version)

From the manual ([url=http://manual.b2evolution.net/System_requirements]this page[/url]):-

memory_limit

Since version 1.8 b2evo often requires more than the default of 8MB of memory. To change it, set the "memory_limit" php.ini value to e.g. 16M. E.g. in /conf/_basic_config.php add the following line:

ini_set('memory_limit', '16M');

It's recommended to set this value in php.ini or .htaccess (for Apache) itself. If PHP is running is safe mode, using ini_set() to bump the memory limit seems to have no effect - ask your webhost provider then.

Note: if you only have PHP 4.1, we recommend you use version 0.9.2

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