sage odbc connection

I am trying to connect to Sage Line 50 data files through odbc
driver (SageLine50v8) from php5 (running on Windows XP pro) by
odbc_connect().
Unfortunately I can not find right connection string and I get back an
error:
"SQL error: Cannot find all files in data path, SQL state 08001 in
SQLConnect"
This is what I am trying to do now:

$connection_string="SageLine50v8";
 $conn=odbc_connect($connection_string,'m
arcin','mypassword','');

I am sure there is the way to connect to this data because I have
successfully connected from Excel using the same odbc driver.

Please advise if you can...
Marcin