We have a mix of AIX and Windows.....example below.
On deleting individual filespaces on AIX there is no problem, as:

del file aixadmin /usr

However, trying to delete individual Windows filespaces causes probems.
All files can be deleted but individula filespaces
specified returns a not found error:

del file afsdbms *............this works

def file afsdbms \\afsdbms\e$..............does not work

AFSDBMS         \\afsdbms\-    1 WinNT    NTFS         No      8,665.1
32.9
                 c$
AFSDBMS         \\afsdbms\-    2 WinNT    NTFS         No      4,297.4
19.1
                 d$
AFSDBMS         \\afsdbms\-    3 WinNT    NTFS         No      8,604.0
20.8
                 e$
AFSDBMS         SYSTEM         4 WinNT    SYSTEM       Yes         0.0
 0.0
                 OBJECT
AIXADMIN        /              1 AIX      JFS          No         64.0
34.3
AIXADMIN        /usr           2 AIX      JFS          No      4,224.0
39.4
AIXADMIN        /var           3 AIX      JFS          No         64.0
57.8
AIXADMIN        /home          4 AIX      JFS          No         64.0
18.9
AIXADMIN        /opt           5 AIX      JFS          No         64.0
18.9
AIXADMIN        /workarea      8 AIX      JFS          No      6,400.0
23.1
AIXADMIN        /usr/sys/i-   10 AIX      JFS          No     25,600.0
16.6