you are right, on windows7 I see the same issue as you. tftp isn’t found. The reason is the file system redirection api
introduced in vista. What you can do, to force that system32 directory is used and not being redirected to syswow64,
is to use the sysnative alias. So your NppExec command must look like this

c:\windows\Sysnative\tftp.exe 192.168.1.4 put C:\1\1.txt

I have tested this on my Winows 7 and it works.

c:\windows\Sysnative\tftp.exe 192.168.178.26 put C:\1\1.txt
Process started >>>
Transfer successful: 9 bytes in 1 second(s), 9 bytes/s
<<< Process finished. (Exit code 0)
================ READY ================

Cheers
Claudia

Can you check which version of tftp.exe you use?
Goto C:\windows\System32
Right-Click on tftp.exe and press version tab.

You are using windows 7 or is it windows server 2008?
x86 or x64?

Cheers
Claudia

can you make a screenshot of your NppExec Execute dialog window and upload to e.g. imgur?

Cheers
Claudia

C:\Windows\System32>tftp.exe -i 192.168.1.4 put C:\1\1.txt
tftp.exe -i 192.168.1.4 put C:\1\1.txt
“tftp.exe” не является внутренней или внешней
командой, исполняемой программой или пакетным файлом.
( “tftp.exe” not an internal or external command, operable program or batch file.)

if you specify the full path to tftp.exe it does not change nothing.
I look through the analyzer (Wireshark) on request packets and see what they are missing.

just tried it with a local tftp server

tftp.exe 1.1.1.1 put c:\1\1.txt
Process started >>>
transfer successful: 10 bytes in 1 second, 10 bytes/s
<<< Process finished. (Exit code 0)
================ READY ================

tftp.exe is a standard Windows tool as well as ftp,ping.

Yes, I know that MS has one but there are freeware tools also available
which then differ in how to run the client and which features are available.
We used to use ms tftp but because of the non existance of -b switch and
the restriction in file size we changed to another product from cisco.
You know, that there is normally a fourth parameter called destination,
which, when skipped, will be assumed as the same as the third parameter, so in your case the remote
computer needs to understand C:\1\1.txt?

Cheers
Claudia

Cheers
Claudia

1. C:\Windows\System32\TFTP.EXE 192.168.1.4 put C:\1\1.txt
2. tftp.exe 192.168.1.4 put C:\1\1.txt
   all item show error:
   C:\Windows\System32\TFTP.EXE 192.168.1.4 put C:\1\1.txt
   CreateProcess() failed with error code 2:
   Не удается найти указанный файл.
   (Can not find the file specified)

But next code working
ping 192.168.1.4

TFTP isn’t part of Notepad++, so must be 3rd party program.
How do you exactly execute your tftp program?
Using F5 or NppExec? Something different?

Cheers
Claudia