[otrs] Installed OTRS2, configured.. then error

[Boniforti Flavio]

Hello list,
here's what I get when I try to connect to OTRS2:

Software error:

Invalid argument at 
/usr/share/otrs/bin/cgi-bin/../../Kernel/System/Log.pm line 79.

For help, please send mail to the webmaster (webmaster at localhost), 
giving this error message and the time and date of the error.

What may be wrong?
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Boniforti Flavio
Provincia del Verbano-Cusio-Ossola
Ufficio Informatica

Tecnoparco del Lago Maggiore
Via dell'Industria, 25
28924 Verbania
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