I recently encountered an issue when installing a 2nd AOS on a server that it failed to install correctly.  The components were attempting to install into an incorrect directory, therefore the install failed as it was unable to register the service correctly.

You may see the following error message within the “DynamicsSetupLog.txt” install log.

AOS.1: Regasm C:\Windows\Microsoft.NET\Framework64\v2.0.50727\regasm.exe   "C:\Program Files\Microsoft Dynamics AX\50\Server\Server\LiveAOS02\Bin\Microsoft.Dynamics.IntegrationFramework.dll"
RegAsm : error RA0000 : Unable to locate input assembly 'C:\Program Files\Microsoft Dynamics AX\50\Server\Server\LiveAOS02\Bin\Microsoft.Dynamics.IntegrationFramework.dll' or one of its dependencies.

An error occurred during setup of Application Object Server (AOS).
Reason: Error unregistering  Microsoft.Dynamics.IntegrationFramework.dll. Program run: C:\Windows\Microsoft.NET\Framework64\v2.0.50727\regasm.exe.  Parms: "C:\Program Files\Microsoft Dynamics AX\50\Server\Server\LiveAOS02\Bin\Microsoft.Dynamics.IntegrationFramework.dll" /unregister

As you can see it’s attempting to install the AOS into an incorrect directory namely:

C:\Program Files\Microsoft Dynamics AX\50\Server\Server\

The correct folder is:

C:\Program Files\Microsoft Dynamics AX\50\Server\

A hotfix exists to resolve this issue it can be download from Customer Source here: https://mbs2.microsoft.com/Knowledgebase/KBDisplay.aspx?scid=kb;en-us;959494

View the knowledge base article on the MS Support site here:  http://support.microsoft.com/kb/959494/en-us