ADMP-PPM file won't install.

ADMP-PPM file won't install.

Hi, 
we're currently on AD Manager Plus v. 6.2.8.1.  I have not been able to successfully update the software to v. 6.3.5.  I have downloaded a few different update versions, in the hope that one might work, but none have.  The error I get is: "The ppm file that you ahve specified is not compatible with this product."
The versions that I have attempted to upgrade using are ""6200 through 6292", "6300 through 6341" and even some of the other, lower versions.
Can you suggest where I might get the correct ppm file from or how I might resolve the issue?
Thanks.
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