Here's my attack on the problem; I used the dos ping command because it sent back a nice message:
The second command escapes the quotation marks
I think you can do this in JMP like this:
my_str = ["key" => 32423];
json = As JSON Expr(my_str);
quote="\!"";
escapedquote = "\!\\!"";
runprogram(executable("ping"),
options({substitute(json,quote,escapedquote)}),
readfunction("text"));
"Ping request could not find host {\!"key\!":32423}. Please check the name and try again.
"
Craige