FX pack 3 problem

Heyya all!
 
I posted the text below in the older SONAR forum, but no replies. As SKOOK suggested to another member, I am reposting it here. If this is inadvertent, ADMIN, please let me know and my apologies ahead of time.
 
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                Hi all.
I did a search on this topic but could not find anything. If there is, I apologize for posting.  
 
Used software/hardware: Windows 7 Pro 64, Sonar 8.53 Studio, i7_950, 24GB, Delta 44.
 
About a year ago, I downloaded the free version of Cakewalk FX pack 3, and installed it to run with SONAR 8.53 Studio. A few weeks ago, I needed Sonar 6 Studio for an old project to transfer onto 8.53. In Sonar 6, I saw Soundstage, which did NOT come up in 8.53, although I could see it in the Plugins Mgr., whereas the other FX Pack 3's effects did come up. I went into FX 3's log file and saw the lines below:  
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Could not Self-Register: C:\Program Files (x86)\Cakewalk Audio FX Pack 3\CWPlugin.dll
Self-Register: C:\Program Files (x86)\Cakewalk Audio FX Pack 3\soundstage.ax
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and then on to Cakewalk Store's site/My account to get FX Pack's serial number; then back to the Registration page. Plugged it in and the Registration program invariably came back with "Invalid serial number".   However, when I plugged in 8.53's serial number, Registration took it (even though I clearly chose FX Pack 3 in the product field) and said "Thank you, your product has been registered", but it did NOT give me a registration number.   What's the remedy here? Anyone know?  
 
Thank you, S.