[Mediawiki-l] Getting an error 500

[Marco 27]

Hello,
I've a problem on my wiki.
When I try to create or modify a page, it get an error 500.
The strange is that it happens only in the page of namespaces User, Project,
100, 102, 104 (but not in ns0, 101, 103, 105, 150, 151).
I tried to follow the page [1]: I put

error_reporting( E_ALL );
ini_set( 'display_errors', 1 );

at the top of my LocalSettings.php, and it shows a problem with
$wgImportSources.
So I deleted it from LocalSettings, but it got the error 500 again, without
further information about the error.
Then I tried to increase memory limit through LocalSettings.php to 16, 32
and 64M, putting

ini_set( 'memory_limit', '32M' );

but nothing changed.
What could I do?
Thank you in advance.
Regards.

[1] http://www.mediawiki.org/wiki/Blank_page#You_see_a_Blank_Page

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Marco 27
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