PHP priner function question(printer connected, but did not print out)

[What What]

I'm trying to print a report to a printer directly using PHP printer
function.
I have code like the following one.
<?
if($handle=printer_open()){
print "Printer Connected<br>";
}
printer_write($handle, "Text to print");
printer_close($handle);
?>

I put the php_printer.dll into the extension folder and added the
printer extension line into the php.ini.

When I tested this code on a server with PHP Version 4.3.9, it worked
fine. When I moved the code to a server with PHP 5.1.1, the printer was
connected, but nothing printed out. I downloaded the php_printer.dll
for version 5.1.1 but nothing improved.

Does any one have adea about this problem? Thanks