preOpenStack Weirdness

[David Burgun]

Hi,

I have a stack that has a preOpenStack handler in the Stack Script. 
When I try to do the following I get a error:

start using stack "/Documents/RunRev/Stacks/Main.rev"

This statement causes an error saying that the Stack Cannot be found 
but I know's is there and if I run this script in a mouseUp handler 
or in the openStack handler it works ok.

Why doesn't this work as expected??

Thanks a lot for your help
All the Best
Dave