Error reading flash (is a directory)

This error means that the file you want to copy from flash to tftp is under a directory.

Follow the steps below

• execute sh flash command

CiscoSw#sh flash
Directory of flash:/c3750-ipbase-mz.122-50.SE5/
    5  drwx        4608   Mar 1 1993 03:09:56 +03:00  html
  424  -rwx     9574343   Mar 1 1993 03:13:20 +03:00  c3750-ipbase-mz.122-50.SE5
  425  -rwx         643   Mar 1 1993 03:13:20 +03:00  info
15998976 bytes total (3625472 bytes free)

• execute command cd flash:c3750-ipbase.mz.122-50
• execute dir

CiscoSw#dir
Directory of flash:/c3750-ipbase-mz.122-50.SE5/
    5  drwx        4608   Mar 1 1993 03:09:56 +03:00  html
  424  -rwx     9574343   Mar 1 1993 03:13:20 +03:00  c3750-ipbase-mz.122-50.SE5.bin
  425  -rwx         643   Mar 1 1993 03:13:20 +03:00  info

• then you can copy ios file to tftp by usinf copy flash tftp command as stated below;

CiscoSw#copy flash:c3750-ipbase-mz.122-50.SE5.bin tftp:
Address or name of remote host []? 192.6.1.57
Destination filename [c3750-ipbase-mz.122-50.SE5.bin]?
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
9574343 bytes copied in 36.054 secs (265556 bytes/sec)