subscription-notifier error report: mysql_fetch_array() expects parameter 1 to be resource, boolean given

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<font size="+2"><b>Newscoop has encountered a problem.</b></font><hr noshade size="1" color="black"><p>
Please take a minute to send us an email.<br><br>Simply copy and paste the error report below and send it to: <b>newscoop-bug@sourcefabric.org</b>.
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    <td colspan="2"><b>Error Report</b>
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    <td nowrap>Error ID:</td>
    <td>2:Newscoop:4.0.2:subscription-notifier:79</td>
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    <td nowrap>Error String:</td>
    <td>mysql_fetch_array() expects parameter 1 to be resource, boolean given</td>
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    <td nowrap>Time:</td>
    <td>Tue, 07 Aug 2012 22:00:03 +0100</td>
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    <td valign="top" nowrap>Backtrace:</td>
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{closure}() called at [:]
mysql_fetch_array() called at [/var/www/vorwaerts/bin/subscription-notifier:79]
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