>For some reason our on error event is not firing. I even tried setting step on and typing "on error" in the command window prior to the line of code that should have issued the error? When this didn't work I typed "on error" on the line preceeding the line of code that should have issued the error.
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>Many thanks.

I noticed the similar behavior. For instance, the form, which has code in Error event, calls a program, which has these lines

local lcOldError
lcOldError=on('error')
on error do myErrorHandling
my code
on error &lcOldError
return

I noticed, that my own error messages were never shown, so the form Error event takes precedance.