If you are getting: "Object Server 01: Couldn't write Visual Studio Project assembly file C:\Program Files\Microsoft Dynamics AX\60\Server\MicrosoftDynamicsAX\Bin\VSAssemblies\Microsoft.Dynamics.Commerce.Headquarters.PricingProxy.dll. Error code 5: Access is denied.".
it can only mean one thing: the security setup for the machine didn't take into account that your AOS user has to have write permissions to the Microsoft Dynamics AX folders.
So, just grant write permissions on the Microsoft Dynamics Ax \60\Server folder (in ProgramFiles) for the user. Or, if you do not want to give this permission to the entire folder, you could just edit the individual nodes, which would be the VSAssemblies, XppIL, and Application folders.