Just another data point - I copy/pasted the script into my script
editor and ran it, and I also get the "variable myReply is not
defined" problem.
Isn't that because you are attempting to set your variable to the
command "reply" rather than a value?
No. The following code sets the variable properly:
tell application "Mail"
set myMessage to make new outgoing message with properties
{visible:true, subject:"this is a subject", content:"This is a test
message."}
myMessage
end tell
--> outgoing message id 284965232 of application "Mail"
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