Can't delete a stack

[Graham Samuel]

I've got a stack that I want to purge in the way the IDE does. At the time of execution of the script below, the stack is in memory with a copy of it in a file (the path is in a global 'gDataStackPath'. I want to destroy both. Part of my script looks like this:

try
      if there is a file gDataStackPath then
         delete file gDataStackPath
         set the cantDelete of stack "myData" to false
         set the destroyStack of stack "myData" to true
         set the destroyWindow of stack "myData" to true
         delete stack "myData" -- this should remove it from memory

This deletes the file as expected, and the IDE shows that the stack is still in memory, but the script crashes on the 'delete stack..' line. The error is 361 "can't set this property".

What did I do wrong?

TIA

Graham