Oracle 817 on Win. 2000

When doing hot backup after putting the datafile in backup mode, OCOPY command gives error, Unable to open input file.
I am copying file from one disk to another disk. Also it displays some junk characters around the file name. File name looks good in V$DATAFILE.

Directory of C:\ORACLE\CORE

05/28/2002 01:14p 524,296,192 SYSTEM_01_TS_01.DBF
1 File(s) 524,296,192 bytes
0 Dir(s) 42,406,957,056 bytes free

c:\ORACLE\CORE>ocopy system_01_ts_01.dbf d:
D:SYSTEM_01_TS_01.DBF
OCOPY - Unable to open input file ☼.P╘☼SYSTEM_01_TS_01.DBF.