저기.. 혹시나 해서그러는데요 변수 선언이 제대로 되었는지 확인하세요 안되셧다면
head.sub.php 인클루드 해보시고요

<form name=fsearch method=get style="font-family:돋움; font-size:28px; color:rgb(102,102,102); margin:0px;"  action="<?=$g4[bbs_path]?>/search.php">
<table border="0" cellpadding="0" cellspacing="0" namo_layoutbox="10,1,1,10,1,1" width="480" height="40" align="center">
    <tr>
        <td width="400" height="40" namo_textbox="0,0,0,0,0,0,0,0,0,0">
           

<table border="5" cellspacing="0" width="100%" height="30" bordercolordark="#333333" bordercolorlight="#666666" bgcolor="white" bordercolor="#333333">
                <tr>
                    <td width="396"><input type=hidden name=sfl  value="wr_subject||wr_content">
<input type=hidden name=sop  value="and">
<input name=stx itemname="검색어" required value="<?=$stx?>" size="55" style="font-family:한컴돋움; font-size:12; border-color:white; border-style:solid;"></td>
                                            </tr>
                                        </table></td>
        <td width="10" height="40"></td>
        <td width="70" height="40" namo_textbox="0,0,0,0,0,0,0,0,0,0"><input type=image src="serch.jpg"  width="69" height="38" border=0 align=absmiddle></td>
    </tr>
</table>
</form>

저가 만든 검색스킨인데

="<?=$g4[bbs_path]?>/search.php - 이부분을

http://도메인/설치된디랙토리/bbs/search.php 라고 변경해서 사용해도 되긴됩니다. ^^

주소를 주실수 잇나요 ?

그리고 form 넣었나요 ?