As you can see, there are many problems with Office version x64 bits:
https://store.suitecrm.com/support/SuiteCRM-official-outlook-plugin
It has been like this for many months.
When can we expect to be able to get and pay for this plugin ?
Hope we can start to spend our money soon 
Are you currently a client of this plug-in and you are running into this error? Or are you just saying that you haven’t bought the plugin yet because you are afraid you will get errors?
I bought it last month, then I experienced this error/bug that make it unusable.
So I uninstalled the plugin, I talked with Jason Eggers, then I got refund (actually first month is free, I just canceled the subscription payment).
And I can see now that the problem seems to remain.
For your information, at the moment archiving from OUTLOOK is failing.
I posted a ticket here: https://store.suitecrm.com/support/SuiteCRM-official-outlook-plugin/1268
Last month, SuiteCRM replied that issue was fix in the next release, so I am waiting of the next release, but there is no announcement about it.
On the support page, you can see that all related tickets are in status : IN PROGRESS