using a checkboxes as filter with mysqli query builder

I used the webassist mysqli query-builder and i probably i did something wrong and need some help.
I have a recordset and 1x input textbox and 4x checkboxes which act as search + filter.

The input textbox filter works, good.... however
the checkboxes seem to respond but i get strange random results

How do i correctly set a filter for every check box?


<b>Here is a simplified version of what my recordset looks like</b>
------------------------------------------------------------------------------------
SELECT tablename.*
FROM tablename
WHERE tablename.country = WAQB_Param1 AND tablename.company = WAQB_Param2 AND tablename.company = WAQB_Param3 AND tablename.company = WAQB_Param4 AND tablename.company = WAQB_Param5
ORDER BY tablename.company ASC
-----------------------------------------------------------------------------------


<b>Here is simplified version of what my PHP code looks like</b>
------------------------------------------------------------------------------------
$filterData = new WA_MySQLi_RS("filterData",$datasheet,0);
$filterData->setQuery("SELECT tablename * FROM tablename WHERE tablename.country = ? AND tablename.company = ? AND tablename.company = ? AND tablename.company = ? AND tablename.company = ? ORDER BY vrzndw_datasheet.col_company ASC");
$filterData->bindParam("s", "".(isset($_POST['searchInput'])?$_POST['searchInput']:"") ."", "-1"); //WAQB_Param1
$filterData->bindParam("s", "".(isset($_POST['filter1'])?$_POST['filter1']:"") ."", "-1"); //WAQB_Param2
$filterData->bindParam("s", "".(isset($_POST['filter2'])?$_POST['filter2']:"") ."", "-1"); //WAQB_Param3
$filterData->bindParam("s", "".(isset($_POST['filter3'])?$_POST['filter3']:"") ."", "-1"); //WAQB_Param4
$filterData->bindParam("s", "".(isset($_POST['filter4'])?$_POST['filter4']:"") ."", "-1"); //WAQB_Param5
$filterData->execute();
------------------------------------------------------------------------------------


<b>This is how the html form looks like</b>
------------------------------------------------------------------------------------
<form id="form1" name="form1" method="post" action="">
<p>
<label for="searchInput"></label>Which the country?
<input name="searchInput" type="text" id="searchInput" />
<input type="submit" name="btnSearch" id="btnSearch" value="Compare" />
</p>
<p>
<label><input type="checkbox" name="filter1" value="A" id="filter1" />Select A</label>
<label><input type="checkbox" name="filter2" value="B" id="filter2" />Select B</label>
<label><input type="checkbox" name="filter3" value="C" id="filter3" />Select C</label>
<label><input type="checkbox" name="filter4" value="D" id="filter4" />Select D</label>
</form>
------------------------------------------------------------------------------------


Is this correct?