Try removing the single quotes from the query string and adding them to the parameter value itself:
$pstmt=odbc_prepare($odb_con,"select * from configured where param_name=?");
$res=odbc_execute($pstmt,array(" 'version'"));
var_dump($res); //bool(true)
$row = odbc_fetch_array($pstmt);
var_dump($row); //bool(false)
The single space character at the beginning of the parameter value is very important–if the space is not there, it will treat the variable as a path to a file.
From http://www.php.net/manual/en/function.odbc-execute.php:
If you wish to store a string which
actually begins and ends with single
quotes, you must add a space or other
non-single-quote character to the
beginning or end of the parameter,
which will prevent the parameter from
being taken as a file name.