Weird behavior from AR

I am using AR on a Windows 7 Ultimate x64 machine and also a Windows Vista Ultimate x64 machine. On my w7 machine the explorer context item to "Add to Advanced Renamer" works perfectly. It adds items selected to the last AR window that was selected. However on my Vista machine when I select Add to Advance Renamer it will open a new instance of AR every time I select this option from the explorer context menu even if there is already an instance of AR open at the time.

How can I change this behavior on my vista machine so it is actually useful.

Thanks.

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