Data Pump Import: can I map an oracle directory object to a shared directory residing on a remote box?

Oracle DB 10.2.0.3   /  Windows 2003:

Seek to DATA PUMP IMPORT from dumpfiles residing on USB HD connected to local workstation.  Have shared the directory containing DATA PUMP EXPORT dumpfiles on connected USB HD so that it is read/write to users on remote DB server.  On remote DB server, I have mapped the visible USB HD share as 'Q' drive.  Created an Oracle DIRECTORY OBJECT called 'xDump' to reference the 'Q' drive and a DIRECTORY OBJECT called 'zDump' to reference a local directory on the DB server to house import logs.

Issue following DATA PUMP IMPORT command

>impdp schemas=www,zzz parallel=5 dumpfile=xDump:schema_%U.dmp logfile=zDump:schema_import.log

I get the following (generalized) errors:

39001:  invalid argument value
39000:  bad dump file specification
31640:  unable to open dumpfile 'Q:\xDump\SCHEMA_01.dmp' for read
27041:  unable to open file
O/S Error:  (OS3)  system cannot find path specified

I assume Oracle Directory Objects can only reference local drives and not mapped network shares as I have attempted.  Please share your expertise.

v/r