require_once 'Date/Date.php';
$date = new Date(time());
echo $date->format('%A %e of %B, %Y [%R %Z]'),"\n";
$date->convertTZbyID('US/Eastern');
echo $date->format('%A %e of %B, %Y [%R %Z]'),"\n";

produces:

Wednesday 1 of January, 2003 [18:39 PST]
Wednesday 01 of , 2003 [21:39 EST]

This patch will fix it:

Index: Date.php
===================================================================
RCS file: /repository/pear/Date/Date.php,v
retrieving revision 1.7
diff -u -r1.7 Date.php
--- Date.php    12 Nov 2002 18:11:10 -0000      1.7
+++ Date.php    2 Jan 2003 02:41:32 -0000
@@ -532,6 +532,9 @@
 
         list($this->year, $this->month, $this->day) =
             sscanf(Date_Calc::daysToDate($d), "%04s%02s%02s");
+        $this->year  = intval($this->year);
+        $this->month = intval($this->month);
+        $this->day   = intval($this->day);
     }
 
     /**
@@ -580,6 +583,9 @@
 
         list($this->year, $this->month, $this->day) =
             sscanf(Date_Calc::daysToDate($d), "%04s%02s%02s");
+        $this->year  = intval($this->year);
+        $this->month = intval($this->month);
+        $this->day   = intval($this->day);
     }
 
     /**