Have you used the Script Debugger to step through the script and see what is happening?
Perhaps you have a script trigger set to run this script too?
Do you have an event script plug-in such as DoScript or zippScript installed ?
What is the first script performed in your session ? is it this one ?
If the answer is yes to both questions, then this is a legacy bug that I work around by disabling the plug-in before the New Window step and enabling it back right after.
This cannot, as far as I know, be reproduced for every file or every script in a file, but happens from time to time, always with the same script.
Are you using a script trigger?
No script trigger. This is just sub script run each time other scripts run to keep track of them. I am a developer and have the Advanced FM 10 and have run the debugger. That is how I know what step is screwing up. It is interesting because when running the debugger and it gets to this step... it starts opening windows over and over even though I clicked only one step in the debugger... it continues to open hundreds of windows until I escape. I tried erasing that step and putting it back in to no avail. I tried adding a Window Name to the New Window step and it still gave me the same problem as with no Window name given.
No plugins installed... only FM 10 Advanced. Actually, the file is hosted on FMSA10.