From the error message (unless you *really* installed P3D4.3 into E:\P3DV3, which seems strange ), the most likely cause is that you had P3D3 installed, but removed it in the wrong way, likely without running the uninstaller and just removing its folders, which would cause your registry key still containing the P3D3 installation data, which is confusing the Control Panel.
Or, you might have used the highly dangerous "Migration Tool", which is acting in a similar way, and of course will cause issues to proper P3D products that needs to recognize the different P3D versions and their difference with FSX, which is precisely what the Migration Tool screws with.