'C:/Program' is not recognized as an internal or external command

After installing Dezyne at path with space you can encounter such a bug:

No matter if Dezyne was added to PATH or not, Windows will still have problems running commands if path consists space. That’s why it is highly recommended to change default .msi installer path.

SOLUTION1:
Replace the installation path with one that does not contain spaces, for example:
C:\VerumSoftware\VerumDezyne

SOLUTION2:
If path to Dezyne folder look as follows: “C:\Program Files\VerumSoftware\VerumDezyne\dzn.cmd”
you can use short name of “Program Files” which is “PROGRA~1”
First, nawigate to VerumDezyne dir:

cd /d C:\PROGRA~1\VerumSoftware\VerumDezyne

Then, you can normally use ide/dzn commands:

C:\PROGRA~1\VerumSoftware\VerumDezyne>ide
Usage: ide [OPTION]… COMMAND [COMMAND-ARGUMENT…]
-d, --debug enable debug ouput
-h, --help display this help
-p, --skip-wfc use plain PEG, skip well-formedness checking
-v, --verbose be more verbose, show progress