Create System DSN MAS90PHP best if you copy SOTAMAS90 DSN add username and password to it. And make sure you run apache under user that has access to mas90 share even in mas200. Below is code that you can test connection with.

<?php
$conn = odbc_connect('MAS90PHP','','');
if (!$conn)
{exit("Connection Failed: " . $conn);}
else
echo"Connected<BR>";

$query = "SELECT * FROM GL_Audit";
$result = odbc_exec($conn, $query) or die(odbc_errormsg());

while(odbc_fetch_row($result)){
echo odbc_result($result, "FieldName") . "<br>";

}

odbc_close($conn);
echo"Connection Closed";
?>