แทรกโค๊ดแบ่งหน้าแล้วขึ้น error แบบนี้คับ...Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result

<form>                	  
					  <table width="490" height="25" border="1" align="center" cellpadding="0" cellspacing="0" bordercolor="#FFFFFF" bordercolorlight="#999999" bordercolordark="#FFFFFF">
                        <tr class="title_table">
                          <td width="36">ลำดับ</td>                          
                          <td width="155">ชื่อ </td>
                          <td width="155">วันที่ / เวลา </td>
						  <td width="80">คอร์ส</td>
                          <td width="49">ห้อง</td>
                        </tr>
                        <?
					$sql2="select member_id from member where user_id='$user_id' ";
					$dbquery2=mysql_db_query($dbname, $sql2);
					$result=mysql_fetch_array($dbquery2);
					
					$member_id=$result[0];						
					
				if($course)
					{					
					$sql="SELECT member.name, selectcourse.course_date, selectcourse.coursename, selectcourse.place
					FROM
					`coursedata`
					Inner Join `selectcourse` ON `coursedata`.`course_id` = `selectcourse`.`course_id`
					Inner Join `member` ON `coursedata`.`member_id` = `member`.`member_id`
					where selectcourse.coursename LIKE '$course'
					and selectcourse.course_date BETWEEN '$start_date' AND '$to_date'
					ORDER BY course_date";
 					}
 					else
					{
					$sql="SELECT member.name, selectcourse.course_date, selectcourse.coursename, selectcourse.place
					FROM
					`coursedata`
					Inner Join `selectcourse` ON `coursedata`.`course_id` = `selectcourse`.`course_id`
					Inner Join `member` ON `coursedata`.`member_id` = `member`.`member_id`
					order by course_date ";
					}
				//echo $sql;
				
				$dbquery  = mysql_query($sql);											
				$order=1;
				while($result=mysql_fetch_array($dbquery))
				{
					$date = $result[course_date];
					list($year, $month, $day) = split('[/.-]', $date);
					$date =  "$day-$month-$year";									
					//echo $date;
					echo"<tr>
						<td align='center'>$order</td>
						<td>$result[name]</td>
						<td align='center'>$date</td>
						<td>&nbsp;$result[coursename]</td>			
						<td align='center'>$result[place]</td>";
						
								?>
						</tr>
                    <?
					$order++;
					}
					?>
                      </table>               
                </form>



เมื่่อแทรกโค๊ดแบ่งหน้ามันจะขึ้น error 
Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in C:\AppServ\www\fitness\count_course.php on line 247

<form>                	  
					  <table width="490" height="25" border="1" align="center" cellpadding="0" cellspacing="0" bordercolor="#FFFFFF" bordercolorlight="#999999" bordercolordark="#FFFFFF">
                        <tr class="title_table">
                          <td width="36">ลำดับ</td>                          
                          <td width="155">ชื่อ </td>
                          <td width="155">วันที่ / เวลา </td>
						  <td width="80">คอร์ส</td>
                          <td width="49">ห้อง</td>
                        </tr>
                        <?
					$sql2="select member_id from member where user_id='$user_id' ";
					$dbquery2=mysql_db_query($dbname, $sql2);
					$result=mysql_fetch_array($dbquery2);
					
					$member_id=$result[0];						
					
				if($course)
					{					
					$sql="SELECT member.name, selectcourse.course_date, selectcourse.coursename, selectcourse.place
					FROM
					`coursedata`
					Inner Join `selectcourse` ON `coursedata`.`course_id` = `selectcourse`.`course_id`
					Inner Join `member` ON `coursedata`.`member_id` = `member`.`member_id`
					where selectcourse.coursename LIKE '$course'
					and selectcourse.course_date BETWEEN '$start_date' AND '$to_date'
					ORDER BY course_date";
 					}
 					else
					{
					$sql="SELECT member.name, selectcourse.course_date, selectcourse.coursename, selectcourse.place
					FROM
					`coursedata`
					Inner Join `selectcourse` ON `coursedata`.`course_id` = `selectcourse`.`course_id`
					Inner Join `member` ON `coursedata`.`member_id` = `member`.`member_id`
					order by course_date ";
					}
				//echo $sql;

				$dbquery = mysql_query($sql) or die ("Error Query [".$sql."]");
				$Num_Rows = mysql_num_rows($dbquery);
				
				$Per_Page = 20;   // Per Page
				
				$Page = $_GET["Page"];
				if(!$_GET["Page"])
				{
					$Page=1;
				}
				
				$Prev_Page = $Page-1;
				$Next_Page = $Page+1;
				
				$Page_Start = (($Per_Page*$Page)-$Per_Page);
				if($Num_Rows<=$Per_Page)
				{
					$Num_Pages =1;
				}
				else if(($Num_Rows % $Per_Page)==0)
				{
					$Num_Pages =($Num_Rows/$Per_Page) ;
				}
				else
				{
					$Num_Pages =($Num_Rows/$Per_Page)+1;
					$Num_Pages = (int)$Num_Pages;
				}
				
				if(!$course){
					$sql .=" order  by course_date DESC LIMIT $Page_Start , $Per_Page";
				}
				$dbquery  = mysql_query($sql);
				
				$order=1;
				while($result=mysql_fetch_array($dbquery))
				{
					$date = $result[course_date];
					list($year, $month, $day) = split('[/.-]', $date);
					$date =  "$day-$month-$year";									
					//echo $date;
					echo"<tr>
						<td align='center'>$order</td>
						<td>$result[name]</td>
						<td align='center'>$date</td>
						<td>&nbsp;$result[coursename]</td>			
						<td align='center'>$result[place]</td>";
						
								?>
						</tr>
                    <?
					$order++;
					}
					?>
                      </table>               
                </form>
                
                <span style="margin-left:10px">หน้า : </span>
                <?
                if($Prev_Page)
                {
                    echo " <a href='$_SERVER[SCRIPT_NAME]?Page=$Prev_Page'>< </a> ";
                    //echo " <a href='$_SERVER[SCRIPT_NAME]?Page=$Prev_Page'><< กลับ</a> ";
                }
                
                for($i=1; $i<=$Num_Pages; $i++){
                    if($i != $Page)
                    {
                        echo "[ <a href='$_SERVER[SCRIPT_NAME]?Page=$i'>$i</a> ]";
                    }
                    else
                    {
                        echo "<b> $i </b>";
                    }
                }
                if($Page!=$Num_Pages)
                {
                    echo " <a href ='$_SERVER[SCRIPT_NAME]?Page=$Next_Page'> ></a> ";
                    //echo " <a href ='$_SERVER[SCRIPT_NAME]?Page=$Next_Page'>ถัดไป>></a> ";
                }
				?>