weird problem php mssql

Hi, I've strange problem with a blob field in a mssql db containing a ms word document: <?php $conn = mssql_connect('hostname','xxxxx','yyyyy'); mssql_select_db ('docs'); $i_result=mssql_query('Select * from documenti_file where file_esercizio_doc = 2004 and file_id_doc = 200'); $ar_row = mssql_fetch_array ( $i_result); echo $ar_row[7]; $file = fopen('test.doc','wb'); fwrite($file,$ar_row[7]); fclose($file); mssql_free_result($i_result); echo "<br>". strlen($ar_row[7]); ?> works ok using my box as server (apache 1.3.29 and php 4.3.4 - win xp) and I can read the written file with ms-word; now the strange thing: running same script on another server (apache 1.3.28 and php 4.3.4 win nt) I got the same result on the screen (echo), but the file written is corrupt and it shows weird things when opened with ms-word. It seems like data got corrupted in the write() task. File size is exactely the same. Database used is the same and resides on a third box. I've the same mssql client dll on the two boxes (ntwdblib.dll ver. 2000.80.194.0) Any idea ?