php - How to configure wampserver for spatialite

I am in windows 7. I installed WAMPServer. Now, I can not load spatialite libraries. It is showing warning..

Warning: SQLite3::loadExtension() [sqlite3.loadextension]: Not supported in multithreaded Web servers

Here is my total configuration procedure, what I have done...

From this link I got spatialite lib. I copied "libspatialite-1.dll" and paste it to "D:\wamp\bin\php\php5.3.8\ext" which contains php extention dlls.

http://www.gaia-gis.it/spatialite-2.3.1/libspatialite-win-x86-2.3.1.zip

Then I edited php.ini file. I changed the following configuration.

.
sqlite3.extension_dir = C:\libspatialite-win-x86-2.3.1\bin
.
extension=libspatialite-1.dll
.

enable_dl = On

And lastly, I copy and paste all the libraries from my downloaded libspatialite-win-x86-2.3.1 to my project folder(libspatialite.a, libspatialite.dll.a, libspatialite.la) in my php code i write the script as follows...

$db = new SQLite3('sixcommunes.sqlite'); 

$db->loadExtension('libspatialite.a'); 

$rs = $db->query('SELECT spatialite_version()');

while($row = $rs->fetchArray()){
    print "
SQLite version: $row[0]
";
}

?>

I do not know what I have done wrong or how to solve this problem?