parse error, expecting `T_STRING'...?

[admin]

System: PHP4.06 + Mysql3.23.41 Win32 + Apache 1.3.20 Win32

$res=mysql_query($query);
$num=mysql_num_rows($res);
for($i=0; $i<$num; $i++) {
$arr=mysql_fetch_array($res);
...
}

When PHP is running at line: $arr=mysql_fetch_array($res);
The IE always show info as below:
"Parse error: parse error, expecting `T_STRING' or `T_VARIABLE' or `T_NUM_STRING' in
c:\program files\apache group\apache\...\page.php on line ..."

What's the problem?

Thanks!