Re: configuration problem
Hi Enric and welcome to Tiki Community! 
(and maybe welcome to the Catalan subset of that community, if so... your name looks like... )
Ensure that yor hosting allows 32Mb (at least) as memory_limit in php.ini for php applications.
You can check that memory_limit value in tiki-phpinfo.php of your tiki installation.
It's explained in the Requirements
Cheers
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