Problems with cron

[maskeret]

Hello,
I'm read all post in this forum about "cron", but I have still problems
I set a cron job by "Cpanel" in this way:
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/usr/local/bin/php -f /full_path_phpdig/admin/spider.php forceall > /full_path_phdig_spider/spider.log
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But this does not work (either with "all" it does not work).
In the spider, log I read:
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9307: old priority 0, new priority 18
Spidering in progress...
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SITE : http://www.mydomain.com/
Exclude paths :
- @NONE@
No link in temporary table
links found : 0
Optimizing tables...
Indexing complete !
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No one document was indexed.
Where I am wrong?
Thank you very much.
Maurizio Mascheroni