I am running Windows 7 64bit with Agent 4.5 and 8.7i patch 2 with Hotfix 517265 (fixed a McTray erroring issue). Works fine. The only thing that I am noticing is that the policies are not getting implemented through EPO to my computer. Haven't started to look in to this yet.
A couple of bits of information for you.
I would upgrade to the latest Agent also.
The PCs have agent 4 patch 3 installed at the moment. Should I install 4.5?
If you are running ePO also install the latest release.
NOTE: If VirusScan Enterprise (VSE) is managed by ePO 4.x, check-in the VirusScan extension update package released with Patch 2 (not the repost).